This is the way most of the computing market has worked most of the time. Mainframes and minis were this way, then almost all the workstation vendors had their own CPU architecture and OS (often a flavour of Unix). The only real exception, and I admit it is a huge one, in Wintel but outside that in house hardware/software development in tandem has been the norm.

Furthermore this model is fundamental to the ARM architecture. The whole point is for licensees to develop SOCs with their own custom components on the same die. That's literally what a SOC is.