More game theory nonsense, sorry also Spoilers
your will to fix the past is strengthening, so shouldn't Echo get stronger?
Euca doesn't even know what his wish was/is
And Echo doesn't want to tell us or complete that wish, so that's probably why he is not getting stronger (also is called a broken star)
we don't even know who brought him (remnant) into existence.
Remnant said he was created by Euca in Sissel's route, and Remnant also said that he finally granted Euca's wish, but Euca decided to go back
Is he the result of a really fucked up Echo, after avoiding his whole purpose, and remained after Halley rewound time, who is he even linked to?
I personally think Euca's wish was a death wish, like he was so depressed that his will to die was immense and that's when Echo was summoned, but since Echo didn't want to do it he got corrupted and turned into a Remnant. (Speculation) Quote from Echo
"No seriously, Euca, it was a *really* stupid wish. I was inches away from punching you in the face."
Also they both have a similar Noose like string around their necks, but Remnant's doesn't have a camera attached, and Echo loses an arm in Owen's route like how Remnant has no arms. (More speculation)