In out family we've had a whole lot of ski cars over the years. Too many. I'm not so sure that the crappy driving conditions described above really materially accelerated suspension problems.
Some cars are just not "great" with suspension wear. Worst in our experience were a couple of Audi avants. The things ate control arms, shocks lasted about 60-70K before the ride suffered. By a bit over 100K, it seemed like every bushing on the car needed to be renewed.
I've commented to
@Monique that her Outback XT sounds remarkable. Like ready for the hall of fame, because in three of them, we had pretty much replaced the entire suspension by 150K miles. With both the Audis and the Subies we had friends who do not regularly ski who had similar problems.
We also have friends who I know kept driving cars with "bad" suspensions, and ignored it, or didn't notice! And we have had friends who have driven a lot of basic transportation for many miles, through a lot of terrible weather with no issues. So I guess,
It all depends.
Our son has a 2002 Tacoma with about 250K miles on it. He did a lot of suspension work at about 120K, and upgrades shocks, springs, the quality of a lot of the bushings. I think he needs a couple of control arms now. Not bad, but on their way out. That vehicle has been remarkable.
We're on out third Land Cruiser, over about 22 years and maybe 750K of driving. Those things are just another build quality. Even with those, we'd typically replace shocks at 100K intervals, watch the bushings for wear.
I just don't think the winter road "crap", of which we have plenty here in New England, made the wear worse.
Have a fried in ski country with an older Volvo 740 wagon that I don't think he has done a thing to in recent years. Must have 350K on it. Still seems to be "fine."
Back on track. I would keep the 4Runner through law school.