Iirc several distributions tried out tmpfs-based /tmp a few years ago then reverted. I think the problem was just that some Linux-specific software and sysadmin

Iirc several distributions tried out tmpfs-based /tmp a few years ago then reverted. I think the problem was just that some Linux-specific software and sysadmins had grown up expecting to be able to write a lot of data to /tmp. Limiting it to 50% of RAM (the default iirc) didn't go well. The distribution people didn't want to deal with converting those things to use /var/tmp so they backed off. I don't think it helped politically that the systemd people were pushing it, as those folks were already perceived in some circles as dictating too much about the direction of Linux. This is all from memory and I'm on my phone, so no citations. In any case, I don't think inode numbers were the problem.