Why wouldn't they? If some companies are that invested in keeping their data off the cloud (on which I agree that those are few and far in between) I could easily this as an on-prem instance.
there goes the business model, including the velocity. do you even startup, bro? sorry for that. a cheeky way to say, growth rate is critical in a funded business like this. an on-prem product is hard enough, an on-prem security critical product, whose entire reason for on-prem is the security aspect? it would kill them.
on-prem doesn't even make sense for the 99% that aren't concerned about the security of it, as long as someone else is responsible for it.
lastly, the rate of implementation and tweaks to integrations for such a thing is going to be very, very high. there is just no sensible way to deploy this on-prem. (selling and supporting an on-prem product is very different from developing your own in-house solution.)
on-prem doesn't even make sense for the 99% that aren't concerned about the security of it, as long as someone else is responsible for it.
lastly, the rate of implementation and tweaks to integrations for such a thing is going to be very, very high. there is just no sensible way to deploy this on-prem. (selling and supporting an on-prem product is very different from developing your own in-house solution.)