I spent the crash in the financial industry which was hit in its own way: one fire-sold company office, one closed satellite office with a job transfer to a consulting company maintaining the same codebase for the company who closed the sat office. That last was my worst job ever but paid rent. The day the final retention bonus/bribe to take the consulting gig hit my bank, 6 of us resigned to come over to our next early-mid-stage startup. My ex-colleagues from the original office seemed to have slower job searches but all found interesting and fruitful work. (The office was a D. E. Shaw & Co. office: fully staffed with higher than average caliber devs. All found work reasonably quickly.)
In the 2008 GFC, that was much less a tech bubble and more a general financial issue. Our company just grew more slowly as the world worked itself out of that crisis, so I have no meaningful insight about that one.
To the extent that this “bubble” feels much less severe than 1999, I suspect more than 3/4 of qualified devs will do just fine in any tech bubble burst. Terrible devs barely hanging onto their job now could easily be shaken out into another field. That might even be better for them overall.