I think it's a mistake to think of it as simply replacing the 2018 version of Whalen-Moore-Brunson-Augustus, which, largely for the reasons you stated, was only good enough for an 18-16 record and 7th place in the standings.
What they're trying to do is chart a succession path while replacing (or phasing out) 4 of 5 franchise pieces who won 4 WNBA titles in a 7-year span. Probably the second-most dominant team in WNBA history, second only to the Comets team that four-peated in 1997-2000. That's what they're replacing.
I was speaking more to the limited context of the various flavors of "Look at what the Lynx lost and they still ended up with the same record as 2018!" that I've seen used as an argument for Collier's ROY candicacy.
I just think you'd rather have the 2019 versions of Robinson, Sims, and Dantas instead of the 2018 versions of Whalen, Augustus, and Brunson at those same spots.
Napheesa was more directly replacing Maya at SF. Her PER finished slightly under Maya's from last year (19.4 vs. 18.5) but she actually came out ahead in Win Shares (5.2 vs. 4.1). She was very much comparable to 2018 Maya, which is very impressive.
Certainly, as recently as 2017 those supporting players for Minnesota were much better than Napheesa's supporting cast now. Which is why neither the 2018 or 2019 editions of the Lynx reached the heights of previous editions of the team. You can't imagine 2017 or earlier Whalen and Augustus ever laying an egg in the playoffs like Sims and Robinson did last night.
So I very much agree that Napheesa is the first block of Minnesota rebuild that will likely take a few years. But if we're just looking at 2018 vs. 2019, I think the surrounding talent that Collier had this year compared to Maya last year is pretty comparable.
(Obviously the fact that we are comparing a rookie to Maya is the crazy thing and why Collier is the ROY!)