They are already running windows on m1 Macs and getting faster geekbench scores than Microsoft surface devicesThis performance benefit of the new silicon sounds interesting for people considering swiching from PCs.
Other than that, your assessment does not make a lot of sense.
Intel and Apple were never competitors for chips. Intel was supplying chips for Apple, and Apple were using them for their computers.
They probably figured that they can increase their margins further and customize the silicon for their own needs if they control chip production. That way, they can also lock out people from using their own hardware (Hackintosh) in the future, as well as potentially lock in customers who can no longer boot Windows or Linux on their hardware because the new Apple chips might not be compatible.
If anything, AMD destroyed Intel, but I think it's really Intel that destroyed Intel by mismanagement and resting on their laurels far too long.
Intel and Apple were not competitors and they won't be competitors in the future, as the only thing Apple's chips will ever power are Apple devices.