If Google suddenly went out of business and 5% of xooglers started companies, we would see a gigantic burst of innovation in computing.
It’s not the whiteboard interviews that makes that possible. It’s the prestige (especially from a few years ago), job security and salary. And the opportunity to work with other smart people. Google has an excellent talent pool.
One of the most detestable parts of Google are all the people with a smarmy self entitled sense of elitism. I had someone get off of a call, and they showed utter contempt for the customer, because in their words, "if they were smart enough they would work here, and every one wants to work here, therefor they are dumb and I shouldn't have to deal with stupid people" What a fucker.
We went back and forth. He readily admitted he didn't know anything about rails. But his position was essentially that because he worked at google, he was smart enough to know rails is bad without needing to actually know anything about it. He was beyond needing any facts or experience to know it was bad.
It was amazing. I've never seen someone convince me they were an absolute tosser like that before. Nothing I could say would make him think twice about his stupid opinion.
But, Google isn't that one guy. They have 183 000 employees. Thats a really large number of people - more people than most of us will meet in our lifetime. They have some entitled wankers for sure. But also, some of the best people I've ever worked with are googlers or ex-googlers. I'm sure Apple, Microsoft, Amazon, etc are just the same. You don't really work with the hundreds of thousands of people at the company. You work with the dozen or so people on your team. At the end of the day, getting on with them is what actually counts.
The world would change, but I think quite a bit less than you seem to think. To put it another way, the world was undeniably changed by Google, but the change has been done, and they're no longer necessary to keep the biggest changes from reverting. (I'd be more worried about SBCL development if google flights' backend couldn't find a new home -- the product itself has tons of competition + just going directly to airlines.)
In actual reality, of course, these things don't disappear overnight, making the pain of switching much, much less for businesses and individuals heavily dependent on some of these things. Even if "google collapsing within a few years" was likely (they have something like a third or more of annual operating expenses saved as cash on hand), a few years is more than enough time. If a business can migrate off of Salesforce or SAP (it can be expensive and time consuming but you can do it!), it can migrate off these.