I have used
exclusively Thinkpads since 1997.
The one I bought in 1999 broke through a cracked screen when a pencil got wedged between the frame and the screen because the hinges were not as strong as those today.
The T42, T43 and T60 series were absolutely incredible for their times but were now without fault; even back then they screen bezel was huge and you had to pay unreasonable money to get a screen with a higher resolution than 1024x800.
My Z60 was a fantastic machine that I ended up giving away. Its battery life, however, will not be missed.
My last T420 has an assembly that flexed far more than I liked and buttons whose pretty uniform black wore out with use, but I still keep it in the closet because it's indestructible. It's ugly as sin though.
I have my minor disagreements with the keyboard design of the X250, but the trackpad is great, the screens have actually usable brightness now with their default configuration, and battery life has gone way, way, way up.
Let's not look at the past with rose-colored glasses. Every one of those machines had a minor issue as far a Linux compatibility (always different), but back then it was a pain in the ass to get the WiFi working, whereas now if anything I might have a complaint about default keyboard bindings. Things change, but at no point in all that time did I have to send any of those machines for repairs (save for the Z60's fan getting clogged with dirt and some random memory module that died).
People get enamored with their machines and their particular quirks, but I much prefer the new, thinner machines. The tradeoffs are tradeoffs, and the defects are just different. Hell I even prefer the new chiclet keys over the old keys.
The only thing I can say is different is that the frame of the newer machines flexes more. That is not a defect; a frame that flexes is far more resistant to falls and impact. All of my machines have fallen off chairs at some point; all of them survived intact.