Sheets has had almost no updates for the last 10 years after getting to its current level of viability. I'm reminded of this 7 year old talk (You Suck at Excel with Joel Spolsky) where he goes over a bunch of great Excel features that still aren't in Google Sheets today.
When the original dev team moves on to other projects, the new guys just make minor tweaks and no major product changes happen. Big new feature releases do things like "we moved this tool from the edit menu to the file menu".
And yet, somehow, some amazing features have been added to Excel recently. Dynamic array formulas and lambda functions have taken my Excel use to the next level. Let alone new standard functions (e.g. sort, filter, misc. text-manipulation functions).
https://www.youtube.com/watch?v=0nbkaYsR94c