Can companies use already-purchased on-prem tooling in the cloud if they want to move to the cloud?

Yes, migrating on-prem solutions to the cloud is often called a “lift and shift” migration, as opposed to building cloud-native systems. But whether this makes sense can depend on the licensing structure. Might be unproblematic for per-user licenses, but could complicate per-CPU licensing. Of course, hardware expenditures are wasted unless a hybrid cloud approach is intended. Administrating cloud-based systems also requires different skills than administrating physical servers.