AI is different.
Cloud computing genuinely is cheaper on average. It's better than paying for cisco servers, and at scale, it's cheaper than managed platforms (ala Heroku), and it's a coin toss for when you're in the middle ground and constantly approaching the point of rebuilding poor-man versions of existing products but with very very expensive engineering salaries.
In contrast, local models offer dramatic savings, and are magnitude of orders better in certain aspects: like stability - the performance is all over the place with traditional AI companies as they divert compute to their next big thing.
The benefits to maintaining your own infrastructure are pretty moderate to low, with very high risk.
And also, alternate models are pretty easy to use and easy to swap out unlike the vendor lock-in that exists with cloud services.