Few jobs are as much fun as being chancellor with £30bn to hand out. For proof, you just had to watch Rishi Sunak this afternoon. Not yet 40, as dapper as a guest at a swanky wedding and presenting his first-ever budget, he wore a giant grin plastered over his unlined face.

Sure, the new boy – on only his 27th day at No 11 – began soberly enough, even trying some Grown-Up Talk about working with opposition MPs on the coronavirus pandemic. But that was swiftly replaced with the usual polemic: jibing at John McDonnell’s “fantasy” economics, declaring “a new era” for the country, and even leading Tory MPs in an extraordinary call-and-response chant on how their government was getting things done. That was a trick lifted straight out of the book of Boris Johnson – and more directly than any other chancellor we’ve seen in the past 10 years of Conservative rule, Sunak used his outing as an audition for the top job.

Chancellor makes £30bn budget pledge to protect economy from coronavirus Read more

If he crowed like George Osborne, he spent like Gordon Brown early in the 2000s. £12bn on measures for the global pandemic, a promise that he would give the NHS “whatever it takes”, and a further £18bn of cash for government departments. Vast sums that Whitehall will be spending over the next year – and a huge jolt for a country used to making do with less year after year. The superlatives flow easily on days like this – yet this budget is markedly less radical than its authors would have you believe.

They break down into two separate sets of policies.The first you might dub the corona budget, drawn up by Treasury officials in the past few weeks as the scale of Covid-19 and its likely impact has grown and grown. An emergency package, its focus is temporary and targeted: on keeping businesses ticking over, and slightly limiting the hit for the one in five workers who could be off sick in the coming few months. Taken alongside the big cut in interest rates on Wednesday , it is now clear that the Treasury and Bank of England are desperately trying to reassure financial markets, businesses and the general public that the state has this in hand.

And yet it simply doesn’t look large enough – especially on statutory sick pay. Johnson declared last week that workers who isolate themselves to protect others from the virus should not be “penalised for doing the right thing”. But the grand sum of £94.25 sick pay a week is just not enough to live on, and the coverage for workers in the gig economy looks very patchy. If Jeremy Corbyn and Labour are smart, they will say that workers are doing the right thing but Johnson’s government is not – and demand it increases both the amount of sick pay and the number of those eligible. And if they do it loudly and quickly enough, they will win this one.

The second part of the budget has been in the works for a lot longer. As I wrote here last week, much of it was put in place by Sunak’s predecessor, Sajid Javid. It is him who Tory MPs have to thank for the money going into Whitehall departments over the next year. Under him, the Treasury laid out the framework for the big infrastructure spending that will be so much a feature of the next half-decade. And it is Theresa May who should nab the credit for the billions about to go into the NHS, because that was her call.

In a democracy paralysed by Brexit for the past three and a half years, few of these announcements got the front pages they deserved – which is partly why politicians and pundits have responded to their reannouncement on Wednesday with a kind of dumbstruck awe.

I can see why. For the first time in a decade, a Tory chancellor has just presented a budget that was not focused on slashing the public realm. Osborne hid behind austerity. Even Gordon Brown pleaded for prudence. But Sunak used no such hairshirt language. Instead, the ex-banker boasted about the size of his budgetary bonus. This is rhetorical territory that no chancellor has dared approach for decades.

Wednesday’s budget underlines how much of the past decade – of punishment beatings for the working-age poor, of slashing public services, of forcing households to the wall while handing billions to large corporations, of polarising an electorate and thereby creating the conditions for Brexit – was simply a political choice. Rates have been at rock bottom for years, the need for investment has been obvious for decades, and the voodoo economics that underpinned austerity was trashed long ago. As Sunak has demonstrated, the strict sanctions for not attending appointments at the jobcentre can be repealed with a snap of the fingers. But Osborne and David Cameron stuck with it because it was politically convenient, just as Johnson has dumped it because it is electorally expedient.

Play Video 'This budget gets it done': Rishi Sunak's enthusiastic pledge – video

Johnson ran for leader promising to slash taxes but now helms a government that vows to increase spending and borrowing. Thus the response in the Westminster village that this was a Labour budget presented by a Conservative government – or the facile retort that the left really has “won the argument”. Both are nice, snappy observations that are utterly false.

The Treasury’s own impact assessment of today’s budget shows that it will put more cash in the pockets of higher earners. Judged by tax and spending, “levelling up” evidently means giving more to those who already have more. Which firebreathing Corbynista or triangulating Blairite would ever have countenanced that? And which Ed Miliband fanboy would have delivered economic policy that gave no more earning power to workers?

Yet Johnson’s first budget was devoid of either redistribution or predistribution. There was nothing to fix the debacle that is universal credit, nor a single extra penny for social care. Public services will remain shrunken and miserly after this budget, even while big developers and civil engineering firms cash in. A prime minister who bangs on about boosting the rest of the country still treats its inhabitants as supplicants waiting for a handout from London. And all the talk of the greenest budget ever was buried under Sunak’s boast of 4,000 miles of tarmac.

Politics will feel different over the next few years, that much is clear after Wednesday’s budget. Even while the economy crawls along, voters will feel the benefit of increased spending, falling oil prices and a rising minimum wage. But the left has spent the past decade fighting austerity and not enough time studying the nature of that most changeable of beasts, Conservatism. It has demanded investment without clarifying who is to be invested in, and called for rebuilding the state without clarifying in whose interests it is to be run.

Johnsonism has taken up some of these demands while ditching anything that might really inconvenience Tory funders and activists. The promise in the last election manifesto to “limit arbitrary tax advantages for the wealthiest in society” was hot air – otherwise Sunak would have scrapped scams such as entrepreneurs’ relief and clamped down on tax breaks on high-earners’ pension contributions. Johnsonism is an election strategy and, as seen in December, a formidable one. But it is not yet a serious programme for government.

• Aditya Chakrabortty is a Guardian columnist