It slows down, along with the rest of the economy during recessions, because it, like everything else, is driven by the same market forces.
My point is that in the average case, there is ~zero opportunity cost or damage to your career, because you worked at MS Azure, instead of... Somewhere else.
You cite fartapp startups that run on rainbows and free VC money, but cloud providers are about as dissimilar from the fartapp as you can get, in terms of their economics and prospects.
You may be bearish on them, that's fine, I can't predict the future, but I see no reason to believe that you're going to have a better life working at literally any other random software firm, during an economic contraction. There's always a few workplaces that tend to be counter-cyclical, but they are, by definition, a minority.
... Also, many government jobs are a political football, that are only as secure as the next election. The best part is that after you worked one, and had half your compensation deferred to retirement, some politician will come along, and campaign on reneging on your pay, after you've given your thirty years of service.