Build their own? Probably not, unless they are doing it at massive scale and the cost of replacing parts beats out buying a server with a 3/5/7 year warranty.

If you have static usage, or at least a base load owning your own hardware to support it does make sense though, colo space is cheap, the biggest disadvantage from a financial perspective to owning your own gear is you have a depreciating CapEx instead of a 100% deductible OpEx.

Real investors care about cash flow, which means the difference between purchasing/depreciating and leasing/renting(OpEx) is negligible. Whats far more important is the business benefits of the best approach for your business.

I don't know what the current state of things is, but 5 years ago they were doing a mix of buying off the shelf and building their own supermicro-based systems.

https://codeascraft.com/2012/08/31/what-hardware-powers-etsy...

Etsy has pay and benefits far outstripping the competition. They should have the best engineers and developers.

So why then can't they build and maintain the best infrastructure? Why does it suck so?