A Tube station front sign from 1909. Photograph: Oli Scarff/Getty Images

We Londoners moan about the Tube as freely as we breathe, but with the underground railway fast approaching 150 years of age we should take a break from carping and reflect on how lucky we are. Though service delays are annoying and the upgrade programme can seem like an unending plague, these inconveniences are trivial compared with what we'd be enduring had the drift of earlier decades gone on. Playing catch up may be trying, but it sure beats grinding to a halt.

A short trip through post-war history makes the point. Starved of investment, a network seen as the best in the world was allowed to atrophy and decline, with only the creation of the Victoria Line bucking the trend. The advent of the Greater London Council brought improvement. Its first Conservative leader Desmond Plummer demanded that old debts be written off and London Transport freed to pump funds into new trains, escalators and lifts, but the consensus view was that public transport as a whole was a fading force as car ownership grew.

It required a shrewd iconoclast, Labour's Ken Livingstone, to recognize the vital importance of the Tube to London. Despite losing a convoluted struggle in the courts he eventually slashed fares and saw passenger numbers soar before Margaret Thatcher, stupid with arrogance, punished London for Red Ken's insubordination by abolishing the GLC in 1986. It took a tragedy, the Kings Cross fire, to bring home the need for more public money and a major organizational overhaul, but the recession of the 1990s saw the tap turned off again.

The introduction of the mayoralty in 2000 created the conditions for the current slow and tortured recovery. Notwithstanding the public-private partnership debacle, the Tube has benefited from two five-year government cash injections since London Underground was brought under the command of Transport for London in 2003, the first under Livingstone restored to the helm of London government, the second under his Conservative successor Boris Johnson. The latter was talked into retaining Peter Hendy as TfL commissioner and should be thankful that Hendy wanted to stay on after being subjected to the smears of Johnson's crackpot media chums during his time under Livingstone. The commissioner deserves his knighthood.

With anniversary celebrations commencing officially next Wednesday – 150 years to the day since the first underground train steamed from Paddington to Farringdon – the future for the London Underground looks brighter than at any time since the suburban expansions of the 1930s. Upgrades (pdf) of the Victoria and Jubilee Lines have been completed. Work on the Northern Line is scheduled for completion next year and on the four "sub-surface" lines – the Metropolitan, Circle, District and Hammersmith and City – by no later than 2018. Plans are being made for the Piccadilly and Bakerloo Lines to benefit from new trains, signaling systems and control centres. Meanwhile, the tunnels for Crossrail are being hewn.

Longer-term, the large questions about the Underground mirror those about London itself. The extra capacity created by the upgrades and advent of Crossrail may barely keep pace with demand fuelled by London's rapid population growth, suggesting that bigger and bolder solutions to the capital's transport problems are needed. The investment programme, which also encompasses expansions and enhancements of Underground stations, depends substantially on revenue from fares. Today, these have yet again risen by more than inflation. Mayor Johnson's commitment to annual hikes is welcomed by TfL, but does nothing to reduce the cost of living for working Londoners on low and middle incomes (not least those underpaid Tube cleaners).

Arrangements with property companies might help finance future line extensions and stations, but the past flashes warning signs. As Christian Wolmar wrote in The Subterranean Railway, the 1990s Jubilee Line extension to Stratford was "designed primarily to satisfy the needs of a private developer rather than London and Londoners as a whole," and that developer's contribution ended up being "minute – less than 5% - in relation to the eventual £3.5b cost of the scheme." It was only thanks to the insistence of London Underground's leadership of the time that stations were built at Southwark, Bermondsey and Canada Water on the way to Canary Wharf. Critics of the proposed Northern Line extension from Kennington to Nine Elms and Battersea argue that contemporary private interests, which are expected to meet some of the cost, are effectively buying up public transport policy along with the land it is purchasing so eagerly for high-end housing projects.

Is the Tube to become complicit in the growth and "regeneration" of London into a place increasingly tailored to the needs of the very affluent? If so, would that be good for London as a whole? And if not, what are the viable alternatives for helping the Underground help London to flourish in the future? Your wise New Year thoughts would be welcome.