At 67 years of age, I'm still learning tons, and the Mavic is a part of that curve. Longevity of the MP is going to be variable, depending on many factors. Maintenance will be a fundamental and watching the motor condition and batteries are a major part of that. Electronics are a whole other matter, and can last a few minutes up to lasting essentially indefinitely. Might be interesting to see what the mean time between failures (MTBF) specs are on the motors and other components. In my work facility, I have an original computer (hard drive included) that is still working well on Windows 95, and that in a dusty environment. Occasional maintenance, and it just keeps on chugging. It is likely that if you don't have crashes, and keep your MP maintained, it can easily outlast you.
After over a hundred hours on my MP, I'm still on the original props and 4 batteries. I haven't even cleaned the lens yet since it has not encountered enough dust or bugs to get contaminated. I've got a lot of ideas on where to fly next and the list is not getting any shorter - if only I had the time.
I'm part of a club that is mostly us "old guys" mostly flying fixed-wing RC, but in the Mavic, I see a whole new crop of youngsters (sorry folks), gals included, who are excited about this technology. We gotta love it.
Keeping the prop side up!