Most if not all of these things are somewhat easy possibilities, just aftermarket - and rather than having a contract type agreement against making TKLs, it's probably more of a reduction of competition. AFAIK leopold actually manufactures some realforces, and the 660C really isn't a bad option if you're looking for a near-stock 60% config. The HHKB has an official "anti-vibration" pad (granted, it's the only official keyboard with one), but it's not too difficult to attach rubber to the feet of any board really. That RF bezel is somewhat required as they have all the electronics for key-scanning and usb handling in the bezel.
I haven't really noticed any play in the keys of any topre keyboard, or any modern consistency issues for that matter. If you do want the consistent silenced 55g, it's possible, but of course you do need to buy 2 keyboards just for it, and with norbauer's work having a metal case is actually a possibility (as well as that usb-c addition).
From what I've heard, SA really doesn't pair too well with topre, but hipro can be wonderful. All of your points are valid additions that topre can work towards, but part of their cleverness is that they have all these features all in separate $200-300 keyboards which causes buyers to spend upwards of like $1500 to get their "dream keyboard".