imo the fragmentation argument is very flaky. this is not like, e.g. the old ARM big endian mode which accidentally created a separate ISA for really dubious reasons. the only thing that really have a need for alternate store orders on ARM at this point are just (x86) emulators. This argument may have made more sense 10, 15 years ago but ARM has become so ubiquitous that the idea of “oh my port of this originally x86 userland software crashes on ARM due to a synchronization bug, better use this TSO thing as a get-out-of-jail-free card “ really doesn’t have much water to it now

There is still interest in emulating x86 binaries on ARM. See the efforts from valve for example.