You can look at something like the headphone jack and say, "adding a jack doesn't prevent anyone from using wireless headphones." But if they get rid of the chip, then it does prevent people from using it.
Short of selling two separate models with different configs, is there any way they could allow the customer to choose?
Apple have taken the decision here that abandoning the ability to recover data from failed machines is worth the guaranteed security floor of it not being possible to disable strong encryption, and honestly I find it hard to disagree.
Obviously if you're worried about nation state attackers you wouldn't want to do that in a million years. But if your primary threat model is that you're an average boring home user suffering data loss because you don't backup and dropped coffee on your Macbook it would be a solution.
From apple’s perspective, hardrive encryption keys aren’t something the average user is going to care about, but files are. The fact that this drives iCloud storage is probably a happy accident ;)
Why? This is something completely up to the manufacturer.
As for forcing HW encryption of hard drives, other companies already tried (WD My Book Duo) and it didn't land well with users.
Until their Macbook dies and they take it to Apple for servicing. At which point they'll care a lot.
I'd hate to be an Apple Genius. They don't half get thrown under the bus by corporate decisions sometimes.
The iPhone outsells the MacBook by more than 10 to 1 and works exactly the same way. I think they'll be OK.
With Bitlocker unless you backup the recovery key in the cloud or manually there is no way to recover it unless you are going to attempt to compromise the TPM this is no different than FileVault/TimeMachine backups which do exactly that however with the added assurance that at least at the writing of this comment the T2 chip cannot be easily compromised or accesses outside of normal operating parameters.