It is worth the exercise to honestly assess the maintenance, initial costs, ongoing costs, etc etc for owning your own. I did this at a company for a single server to let the ml group test fine tuning frameworks/throw crazy ideas at before spending real money on a training run and it paid for itself in like 3 months. Sometimes the math is overwhelmingly positive, sometimes it isn't. In general, the smaller/earlier you are the less it makes sense. Not because of the per hour costs, but because of the distraction away from implementing the core idea of the company. It is worth some, maybe a lot of, inefficiency to stay focused. When you get bigger and have strong fit and a clear direction it is a lot easier to focus on optimizing hosting costs and spending leadership time away from the core problem of the company.