“It’s not impossible, it’s just not available” is not a super compelling defense for a move away from a Bootcamp capable computer.
Nor is "it's not available, so it is impossible".
We're talking about the
feasibility of a
rumour here. Do you really expect developers to be announcing ARM versions of Mac software or emulation solutions for ARM Macs
before Apple have even announced the move - let alone released a development platform?
No, Bootcamp for x86 Windows won't be possible on an ARM Mac. Bootcamp for
ARM Windows will happen if MS and Apple allow it to happen - and, at worst, would be more effective at running x86 Win32 apps using its built-in emulation than running the whole OS under emulation.
Apart from that,
if Apple announce ARM Macs, the majority of Mac applications
that are still actively supported and viable will likely get native versions, because in most cases the work needed will be no worse than the annual testing and possible tweaking for the latest Mac OS release - and probably
less work than the 64 bit transition (which has already killed off most of the likely casualties). Big "pro media" packages will take longer, if only because of all the third party plugins, but unless Apple is insane they'll already be talking to Adobe et. al. under strict NDA.
But
nobody credible will be announcing MacOS for ARM products before Apple announces MacOS for ARM.
Also, remember, the Mac is still the #4 biggest selling personal computer system from the people who pretty much invented (or, at least, rescued from oblivion at Xerox) the modern personal computer - if Apple
does announce a switch to ARM then that fact in itself will be a
huge game-changer. (Intel gained a lot of cred from Apple's Intel switch, which pretty much flagshipped the new Core processors after the Pentium 4 debacle).