Million dollar question - at which point it gets easier to learn how to host things on your own vs keeping up with this cloud mumbo-jumbo bull type of knowledge?
It just always seems a bit salesie to me. Bring your network switching to the "cloud".. yadda yadda. Why? Everything is working great.
The problem is that mostly anywhere else in the world, you can get personell for much cheaper.
For highly volatile workloads, ephemeral workloads, anything where go forward capacity is fuzzy or unknown, cloud is awesome. For anything where your margins aren't robust, or your workload is known and consistent, you're better off going through the schlep of internal IT management (as long as your org isn't dysfunctional and how you operate this is a business enabler, not a hinderance, forcing shadow IT attempts). If you can't generate more revenue or margin, you've gotta look at cost savings, including the cloud premium.
The thing is, I've yet to see any startup even with VC money that has a product which has this need. Most startups nowadays factor away common crud, like booking a service or providing organisational tools. These high pressure, intense workloads are often incredibly unrealistic.
The scalable cloud is useful for scalable workloads (AKA how many times is you peak demand larger than the average?). If you want managed infrastructure, you are looking for renting a managed server or VPS.