The Tiago treadmill

So I've been working on my seismic devastator build bit by bit, when I was around CT10 I was able to sell materials for drop pod resources and re-roll to buy a few legendaries I wanted

But now I'm at CT13 and I get around 4k for completing an expedition but the cost of legendaries is around the 90k mark.

Is there a way to move past this treadmill of increasing prices short of just farming expeditions? It makes the grind feel bad when you get the achievement of completing a CT but are "rewarded" by the prices being even further out of reach.

I know now that there is the method of being carried through CT15 when you are at CT1 to be able to almost unending re-roll and buy what you want.

But without this method am I now stuck having to farm?