I'm not sure which companies you are talking about here. I work for a small startup and between us, we have plenty of experience of maintaining servers but that

I'm not sure which companies you are talking about here. I work for a small startup and between us, we have plenty of experience of maintaining servers but that doesn't mean I would bet my company existence on me not forgetting to setup the firewall correctly. It also doesn't account for all of the out-of-hours stuff we need to do. Even with a hosted solution and a lot of paid-for services like Cloudflare, we still have to check out every unusual error email, everything that seems out of the ordinary. If you are 200+ people, great, you probably already have a team to manage this. If you are small like 90% of companies then you won't and I want to spend my time on the things I am expert in.