That has been my experience too. I've re-wired my fair share of boats over the years and without question the soldered joints are the ones to fail, corrode or both.
The other thing I've found is the wires tend snap just above the solder joint. This is probably due to solder creep which makes the wire more brittle because it's now, in a sense, a single conductor wire and has lost it's multi-strand flexibility.
I do a two part process with a proper marine grade crimp usually made (or sourced) by
Anchor and then over that I use adhesive lined heat shrink and melt it down with my heat gun..