ARM architectural licensees develop their own microarchitectures that implement the ARM ISA spec, they do not license any particular microarchitecture from ARM (e.g. Cortex-A? IP cores). That includes Apple, Samsung, Nvidia and others.
In reality, most of their licenses are processor (core+interfaces) or POP (pre-optimized processor designs).
https://www.anandtech.com/show/7112/the-arm-diaries-part-1-h...
It's much, much easier & cheaper to take the premade core rather than developing your own. But your own custom design gives you the ability to differentiate or really target a specific application. See Apple's designs.
Read the Anandtech article, it goes into more detail on the license types. There's also the newer "Built on Cortex" license: https://www.anandtech.com/show/10366/arm-built-on-cortex-lic...