the thing is that like,,, ok bear with me
a Tails without a Sonic can still be Tails. hes not automatically gonna be fucked without a Sonic (though it can happen). anyone couldve shown him that kindness he needed when he was younger and he wouldve followed them with just as much loyalty
a Sonic without a Tails tho? oh boy. that guy is FUCKED right off the bat. you cant replace his Tails with anyone else because hes gonna turn out to be a prick either way
we KNOW this because he met Amy before he met Tails, and he wasnt exactly friends with her. they were friendly, but he just saw her as just another person to save
a Sonic having a Tails is a Sonic that has grown and become friendlier, more personable, and stronger in-turn
theres a reason why the cosmic truth is that SONIC needs Tails, not the other way around