I'm not so sure that selling both the Amiga and a PC were a mistake
It was not just to sell two competing platforms problematic. It was to manufacture AND sell them.
Is Amiga performance or compatibility more important?
Reducing a problem to one or two questions can sometimes be dangerous.
We should begin by defining compatibility type:
hardware or software (well, okay, here, there are only two questions)?
In general, compatibility and performance should not exclude each other, I would say they are complementary.
The problem lies rather be in their subordination.
And yes, yesterday the 68k was condemned to disappear, mainly because of technological limitations. But is it still valid?
Today, FPGA technology seems promising because it appears to allow to overcome certain constraints.
What is interesting with the FPGA is the abstraction part. This should help to reduce dependence on this technology.