Im not sure this is true, is it? Depending on which regimen you are using. I don't think I would abandon testing ca/alk/and occasional mg if I wasn't doing water changes. I think it would be interesting to hear (and maybe Triton has literature on this) - how many tests they receive that result in an 'actionable result' - especially from tanks that have no sign of problem (either an element that is much to high or much too low - and has been proven to affect tank health).
No I agree, and that's the thing. Honestly IMO running "no water change" can have a lot more work involved then running a WC and forget it style system.
I'm just saying there is a balance on both sides where we have to test regardless of what system we choose. I can tell you from personal experience since taking my 60G to no WC I have done SIGNIFICANTLY more work and spent significantly more time with my equipment and components and testing then I did previously.
As usual YMMV, but I want to be clear there is a BIG difference between LARS and an active reefer running "no water change"