Except apple has demonstrated they can design cpu’s that outperform the (android) competition. Who is to say they can’t make ARM cpu’s that genuinely outperform intel? Intel hasn’t executed all that well lately anyway.
Intel has been iterating their design decades longer and was in stiff competition for much of that time period. They will be hard to catch in the desktop/laptop space for anyone starting with a cell phone CPU.
ARM has not had real competition in their market, most chipmakers are licensing ARM tech, so they should be easier to catch up to, which Apple has done (with a healthy dose of borrowed ideas from ARM).
If they had any doubts all they had to do was say nothing -- which is their strong preference -- and it would have remained clear that the Mac Pro was dead.
Making a strong "trust us, we're working on it" statement and then canceling would be a pretty bad unforced error. Not impossible, but with their top-down, forward-looking decison-making process it seems very unlikely to me.
It's much more reasonable that they'll do a "best effort" in the high end space but it won't be comparable to a Xeon. You can see the iMac Pro as a prelude to that. A beefy machine to be sure but not what you'd expect for top of the line.
But if they really are committed to the Mac Pro (and if this rumor is essentially true), then they must be planning something pretty extraordinary:
1. They actually have a solid plan on how they are going to make CPUs competitive with Intel Xeons over the next ~2-4 years.
2. They're planing on a bifurcated line, where some Macs have Apple CPUs and some have Intel CPUs... presumably with different architectures. I guess 2b. would be that the Apple CPUs will actually be x64 compatible.
It all seems pretty crazy, but Apple has done this kind of thing before, and done it rather smoothly. I guess time will tell.