Just to note that it's not useful to group all of these companies together. While they all have massive valuations, and raised lot of funding, they don't have similar businesses at all, or capital efficiencies. The market is also different today than it was with Microsoft or Google. Companies are expected and also need to grow faster (or others will). It took Microsoft 10 years to break $100M in revenue. All companies on your list are about 10 years old but have revenues in several billions.

WeWork's problem was that while they valuation was $47B, they also had $47B committed in long term leases (essentially debt). Uber & Lyft, are in war and their scale hasn't helped the economics as much since neither can get a monopoly on demand or the supply side of the market. Postmates, Doordash, Instacart, all likely operate with large gross volumes but low transaction sizes and low margins which can be challenging.

Airbnb has now more cash the bank than they have ever raised ($3.5B) and it's growing [1]. I suspect Stripe's financials are strong as well.

Free cash flow, and the ability to use or invest it well, eventually lead to a great business. Raising a lot of money doesn't necessarily mean that you are burning a lot of it, and the economics of the business matters.

It's also likely Airbnb will do a direct listing since they don't actually need the cash. Which is also potentially better for employees than traditional IPOs.

Disclaimer: I used to work at Airbnb, but this is all public information or speculation on my part.

[1]:https://twitter.com/KateClarkTweets/status/11849334122319953...