These days most people have 64-bit computers*. So, will it be too difficult for the developers to include a "Install 64-bit version only" option in the installers of dual-architecture portable apps like Firefox Portable?
*Please refer to these stats: https://www.pcbenchmarks.net/os-marketshare.html
This is planned but it's a bit more complicated. The launcher needs to be able to work with just the 64-bit version within as well. Currently it's written expecting both to be there. So the main PA.c Launcher as well as custom launchers for apps like Firefox, etc will need the rewrite and test and then the functionality added to the installer, most likely in conjunction with a Platform setting.
One side note: Stats like this are misleading as they only report on people who use a specific thing. In this case a bench-marking tool. Users of older 32-bit machines/Windows installs are unlikely to use such a tool. Same with gamers, which make the Steam stats misleading.
Sometimes, the impossible can become possible, if you're awesome!