I can see having both, but tubs need to be more practical & accessible. No more water-guzzling monster tubs, that are difficult to get in out out of! Or "pretty" tubs where even a young, healthy person could easily hurt themselves getting in & out.

I don't think your resale will be effected as long as you have at least one tub in the house. For small kids a tub is a must.

There are discussions about this all of the time on Houzz. Here's a thread that is still being debated.
https://www.houzz.com/discussions/does-a-master-bathroom-need-a-bathtub-dsvw-vd~518674

Agreed, there are items / features that are timeless and invaluable to a house.

If it is the only tub, you most definitely could loose families with small children as potential buyers. Do not forget those who like soakers. I think the huge water and space guzzlers are on their way out and if not, they should be. Of course, you have to consider I am a frustrated recyclist, conservationist, preservationist, whether it be construction materials - for smaller home (I think McMansions are a crime against nature and our fellow humans) or the land to build it on & the beautiful trees torn down, cuz everyone wants, not needs new stuff.