Well, in the case of Ein if you're doing Wing 3 (Pretty much the only non-Odin wing worth doing, occasionally Wing 2 is okay and Wing 1 is pretty much never worth doing) you pretty much need at least 3 people if you want to clear it, so it's not like even if they removed the entry requirement altogether it would matter, because nobody is going to waste 60k on a lamp to enter solo and get a few measly ichors.