FWIW, I am not saying that I think Dropbox made the wrong decision. I'm just not convinced on the prevailing narrative or the long-term viability. Also: the vast majority of businesses aren't Dropbox! Their scale is rare.
Also, because they now have their own infrastructure, Dropbox has to remain organizationally excellent at managing, deploying, and modernizing it. It potentially distracts from other things. Wise long-term bet? I'm not so sure.
A lot of noise about how Dropbox saved $75M over two years by moving off AWS. Most are missing that Dropbox has over $1.1B in revenue. That means that they're saving around 3% of their revenue annually. Much less impressive in context.