I guess I'm coming from the other side with low expectations.
I never expected to see a Files app, external storage support and mouse support on the iPad. I didn't expect to see 16GB RAM on iPads until another 10 years. I didn't expect the x86-ARM transition to happen so quickly and go relatively smoothly.
I've seen posts suggesting this could've been done 5-6 years ago with the 1st gen iPad Pro. However, at the time A9X just reached parity with 2-3 year old Intel desktop chips. RAM was a measly 4GB while my Ivy and Haswell builds were already 16GB with Firefox and Chrome regularly using more than half. Base storage was a paltry 32GB and while storage speeds saw a major improvement over the previous generation's eMMC particularly in terms of sequential performance, it was basically still at mechanical HDD level for random access.
I'm a bit more optimistic now because the building blocks are there in a way they haven't been for older iPad Pros. I don't expect to see macOS running on iPads anytime soon. macOS apps while in docked mode, though? It's actually feasible now.
Regardless, I'm buying the 2021 Pro for what it can do now (mainly 1TB storage, 5G and less reloads/smoother operation compared to my 4GB RAM 2017 Pro). If it does more in the future (whether that be iPadOS 15 or later), then that's just a very, very, very nice bonus.
As far as pricing, it's not even that expensive compared to the 2018 iPad Pro.
2018 iPad Pro 12.9 Launch Prices
Wi-Fi models:
64 GB – US$999
256 GB – US$1,149
512 GB – US$1,349
1024 GB – US$1,749
Wi-Fi + Cellular models:
64 GB – US$1,149
256 GB – US$1,299
512 GB – US$1,499
1024 GB – US$1,899
2021 iPad Pro 12.9 Launch Prices
Wi-Fi models:
128 GB – US$1,099
256 GB – US$1,199
512 GB – US$1,399
1024 GB – US$1,799
2048 GB – US$$2,199
Wi-Fi + Cellular models:
128 GB – US$1,299
256 GB – US$1,399
512 GB – US$1,599
1024 GB – US$1,999
2048 GB – US$2,399