Beside "being able to switch from x86", there are some other factors that make this feat look easier than it actually is:
- building on the ARM architecture, which (1) saved them a lot of design costs and (2) being a simpler architecture already has a "built-in" performance advantage over x86.
- having years of experience already with the "A-series" of chips used in iPhones and iPads since 2010. Everyone is talking about "Apple silicon" now, but these predecessors are often forgotten.
- having a privileged partnership with TSMC, where they have access to the latest and best processes and priority over all other TSMC customers.