Perhaps they aid in some, but calculators don't "solve the calculus problems" I've seen. That's just it; they are an aid, not "the answer." Solution of problems in calculus involves a pretty thorough knowledge of calculus and all that precedes it, and most of that is done with the calculator we're born with.
That's what I mean.
All said and done, the calculator is a tremendous asset *after* an understanding of basic principles of the subject it is supposed to assist. Same with woodworking [thought I'd throw that in.] The tools don't make the master woodworker, but good tools sure help. Lots of people have much better tools than some superb craftsmen stuck with less, but all they do is build stepstools. The calculator [ or CAD program or whatever] is good in the right hands and next to useless in the wrong ones, and really not all that necessary, as you pointed out.