Is $2,000 to re-tape, mud, and paint ceiling joints a fair price?

I have several places in my mid 60s home with cracks in the ceiling at drywall joints. Also have some notable “waves” that coincide with the ceiling joists. I'm concerned that the contractor said the cracks would reappear in “a couple years” no matter what he did due to the age of the house and the climate (upstate South Carolina; stretches of below freezing and occasional snow in winter, currently prepping for upper 90s and >80% humidity). I find it silly to pay $2k for re-taping and mudding + paint for it to all have to be re-done in 2 years and am questioning if this is correct or if there's a more lasting repair process.