I think the real reason to go all in and spend crazy at this point is their high picks won't yield players who will be here soon enough to make an impact. A 2023 1st rounder won't be a NHL regular until 2025 as a best case scenario, and more realistically 2026 or 2027. Who cares if you don't have the next Sam Poulin in 2027 if you measurably improved your chances in 2023-2025 by trading that pick?
Even if you assume Crosby re-signs on a 1 year deal to retire when Malkin retires (which is my bet for what happens), you'll have now through 2025-2026 as years with this core. The 2023 draft to 2025-2026 would be like the 2020 draft to 2022-2023, how many prospects drafted in 2020 are even having a notable impact in the NHL right now? It's really not much.
Even if you want to look at a non-COVID affected year, we can look at how mid to late 1st rounders in the 2017 picks did in 2019-2020. There were definitely a few notable contributors, with Suzuki having 41 points in 71 games, Necas having 36 points in 64 games and Thomas having 42 points in 66 games. But that's really about it, and some of the prospects from that 2017 1st round are just now establishing themselves as contributors. Case in point: POJ, who was taken 23rd overall in 2017.
I think the best case of a 1st rounder around where the Penguins would be picking ascending into a significant NHL player quickly is with Barzal, who was drafted 16th overall in 2015 and was a PPG player in 2017-2018. That's the same 3 year window that guys like Suzuki, Necas and Thomas fall into. But getting that level of play from those picks that quickly is absurdly rare. It's not as uncommon if you're looking at 4-6 years after being drafted, but it's super rare to get someone with as many years as the Penguins core has left.