Thus, the force field environment suits were a cost-saving "compromise," yet also provided options to the story writers.
One of the biggest advantages of TAS was that it was an animated TV series, thus there wasn't any need anymore to "compromise" as they could
have visualized anything
they wanted without considering budget restraints.
The thing with this life-support belts may have been a science fiction concept compatible with the superior 23rd Century technology we'd seen in TOS (transporter and warp drive) but unfortunately just a couple of years after TAS came TMP and EVA space suits were even bulkier than the futuristic ones we'd previously seen in TOS (not to mention that by the 24th Century of TNG they are still using bulky EVA suits).
Thus these "exotic" TAS life-support belts stick out like the proverbial sore thumb in the larger "in-universe" context of Star Trek. If
they were doing a CGI reboot (using the original voices), I do think that it would be an issue worth considering (and to match the original dialogue you could always add something onto the original TOS space suits - provided these didn't already have these unique properties we'd seen in TAS).