Wall Street's two-day-old coronavirus crash is a wakeup alarm for Silicon Valley.

The big picture: Tech has been booming for so long the industry barely remembers what a down market feels like — and most companies are ill-prepared for one.

Background: The tech industry's last real experience of financial adversity was a generation ago, when the dotcom bust leveled the tech sector.

The recession of 2001 hit Silicon Valley extra hard, while the Great Recession of 2007-2009 left it relatively unscathed.

"RIP Good Times," an infamous presentation by Sequoia Capital in 2008, tried to warn tech of a coming downturn that barely materialized — and the following decade turned into a unicorn-breeding, billionaire-minting, IPO-launching Gilded Age for the industry.

Today, most startups and many well-established firms are led and staffed by people who have no first-hand experience of the brutal logic of industry shrinkage.

Veterans of the dotcom collapse 20 years ago recall how it played out then.

Winners:

ROI (return on investment) and cash revenue: Companies that don't rely on borrowed money or equity financing are in a much better position to keep the lights on.

(return on investment) and cash revenue: Companies that don't rely on borrowed money or equity financing are in a much better position to keep the lights on. B2B (business-to-business): services and products with other businesses as their customers tend to fare better than companies that serve consumer markets.

(business-to-business): services and products with other businesses as their customers tend to fare better than companies that serve consumer markets. M&A (mergers and acquisitions): The lawyers and financiers who help growing companies buy out their competitors also make out like bandits in a downturn, when failing companies need to consolidate.

Losers:

Advertising and media: Marketing budgets are easy to cut fast, and media outfits dependent on those budgets feel the pain the fastest.

Marketing budgets are easy to cut fast, and media outfits dependent on those budgets feel the pain the fastest. Employee activism: Layoffs spread fear among workers, job mobility and openings evaporate, companies feel less need to keep their employees happy — leaving workers without the security they need to speak out.

Layoffs spread fear among workers, job mobility and openings evaporate, companies feel less need to keep their employees happy — leaving workers without the security they need to speak out. Diversity and inclusion efforts: While experts say a diverse workforce is good for the bottom line, recruiting and retention efforts require investments that often get pinched in lean times.

While experts say a diverse workforce is good for the bottom line, recruiting and retention efforts require investments that often get pinched in lean times. Idealistic mission statements: "Changing the world" gets swapped out very quickly for "Staying alive."

A coronavirus-triggered recession could affect tech in unexpected ways.

The industry is highly dependent on international collaboration, cross-border supply chains and global consumer demand, all of which are threatened by the prospect of a pandemic.

But a shelter-in-place mentality could prove a boon to videoconferencing, e-commerce, and other tech-driven trends that let lives go on with less direct human contact.

A market retreat could also reshape the inside-the-Beltway critique of Big Tech.

Arguments for tough new regulations based on the industry's power might look different in a world where tech giants' stock had been battered and their spending cut, on everything from lobbying to acquisitions.

20 years ago, a new wave of companies (including Google, founded 1998, Salesforce, founded 1999, and Facebook, founded 2004) germinated while the giants of the era froze in place or withered.

The big question today is whether a downturn would clear space for a new generation of startups to blossom, or just leave today's giants more deeply entrenched.

Yes, but: Two days of 3-percent-plus losses in the market don't constitute a downturn, or even, in technical terms, a market "correction" (which is defined as a 10 percent drop).

Markets took a dive in late 2018 on recession fears, only to come roaring back.

Today's financial world is still awash in cash, which could provide a calming buffer. The venture capital world is still looking to invest huge amounts: Per Pitchbook, funds raised a record $88.3 billion and $75.5 billion in 2018 and 2019, respectively.

In some cases, smaller companies started laying people off even before this market drop, so they might be able to weather it more easily.

The bottom line: This week's precipitous drops remind everyone in tech that graph-lines don't alway move up as they move to the right. The alarm might wake the Valley — but the industry could also just hit "snooze."

Go deeper: