I'll swing at that one . . .
First I'd argue your question is two parts: how long a hull lasts, and how long between major overhauls.
Assuming a hull avoids the normal end of useful live events (dirt, rocks, sand, buoys, other boats, pilings, and other structures either afloat or fixed), and that hull is operated by a reasonably prudent, reasonably sober, reasonably skilled operator, and that hull is not raced aggressively, the HULL (hull, deck, glass structures) is likely good for 30 years or better, plus or minus a decade. J24s (there are over 5000 of them), while not subject to 40 knots of speed or powerful outboards, is also a gelcoat, polyester, end-grain balsa laminate construction. You have to do something REALLY stupid to "end" a J24. Grady White, under prudent use and maintenance, I don't see how it wouldn't last just as long.
The second part of your question is more important, I think. A powerboat has a lot going on, and a lot of powerboat owners are just like sailboat owners; reluctant to take apart perfectly functioning assemblies for the purposes of longevity and maintenance. "Major overhaul," as far as I can see in what I've read on this site alone, falls into 4 categories. 1) full re-wire (water intrusion/corrosion), 2) full re-power (not really "the hull's" problem) 3) wet deck/core (water intrusion/corrosion), 4) fuel tanks (water intrusion/corrosion). Notice anything? To the extent that each spring you tackle a progressive list of "fixes" and investigative, maintenance tasks, is the degree to which you can avoid "major overhaul."
Someone who actually works in the marine industry could probably put an experience says timeline on "if you did no maintenance, or the bare minimum to be launched each spring," how long before a boat looked like a total eyesore, and how long before it's a total loss.