Wiritng cursive has crossed the line for decades (just teach them so they can write legibly, which is still required - but all that cursive shit, no).

However long division and other things such as doing multiplication by hand are important skills that should still be taught: it internalizes the idea that a big difficult calculation can be made easier by turning it into several smaller calculations. It's a bit like learning asm in computer science - you're (probably) never going to use it in the real world but it's important to know in the understanding of how a computer actually works.

If anything I think schools need to be able to get more people to be able to do mental arithmetic and estimation. If you understand these even if you only ever use a calculator it gives you the skills to sanity check the result (how many times have I thought "that's not right" after entering something into a calculator because it disagreed with a mental estimate, then discovered I had miskeyed a number, especially on a touch screen)