It's not a classic thinkpad, but my thinkpad from 7 years ago is still going strong.
Recently I decided to do a service on it for the first time, and I was absolutely stunned by how little dust had built up in the CPU fan and the interior in general, after 7 years of usage, often sitting on top of a couch or bed, near my long-haired Norwegian forest cat Rufus. All it needed was a litle puff of computer duster and it was good as new. That's very good design of the air intakes and is a huge factor in the machine's longevity.
I did computer repair professionally for a while, and one of the most common causes of irreparable death I saw in laptops was massive dust buildup in cpu fans and consequent heat damage to surrounding components. I'd sometimes see this in 2-3 year old laptops even.
Funny to think that something as simple as the shape of an air intake opening can have such a profound impact on the lifetime of a device.
The other thing that Thinkpads are unrivaled at is protection for the display. People like to say macbooks are sturdy, but they are quite prone to cracked displays because of Apple's obsession with smaller bezels. The thinkpad ofc has t34 style angled armor for its display. Can't remember ever seeing a Thinkpad with a cracked display. And I carry my Thinkpad around in just a backpack with no sleeve, often the Thinkpad is the only thing in there, and it regularly impacts the floor when the(thin-bottomed) backpack is put down while sitting down on the bus or getting home.