Do they? Any time I've done FDE it's always been luks with a password, I've never seen one go for TPM by default!
I've only recently implemented luks+TPM on a personal laptop (and that was a PITA to do).
I didn’t find it too difficult to set up TPM backed encryption on Arch using systemd-cryptenroll for my home server, although for anything I use interactively I just use a passphrase instead.