I’d say spending 5k on electronics will contribute more to fishing success than spending an extra 5k on the boat. Ie: 40k + 5k electronics will set you up for success more than 45k + cheapo electronics. Obviously that’s not always the situation you are in.
At least as long you put in the time to learn how to use them and interpret them effectively.
I fish with a dude who’s pretty good with his electronics, amazing how much it helps.
Of course, nothing contributes more to fishing success than how many thousands of dollars worth of crankbaits you own, that we can all agree on.