Some of the most popular ThinkPads, even among diehard ThinkPad fanatics, are from well into the Lenovo era. Say, for example, the X220, X300, T420. They came out several years after IBM stopped having anything to do with ThinkPads, and they are exactly as durable and easily repairable as the old reputation of ThinkPads say they are.
I would go even farther than this. The "real" ThinkPad lines after the T420/X220 generation (T440, X1, W series, etc.) have had many of the traits that make ThinkPads unique, such as the spillproof keyboard, TrackPoint with physical buttons except for the T440 generation, incredibly durable structure, and relatively high upgradeability.
The upgradeability has certainly decreased, but unlike most laptops on the market the losses in most ThinkPad lines typically felt like genuine tradeoffs rather than the product of laziness. I, for one, don't want a machine that weights 2.5 kg or more, and this is possible with the modern ThinkPad line while still having a replaceable keyboard, 14" display, RAM, 2.5" disk drive, two batteries, WLAN, etc.
Thinkpads are not that easily repairable. Accessing the fan assembly is notoriously cumbersome. For accessing the fan assembly in a T420 you need to remove the keyboard, various PCI cards, the speakers and even the display.
• “1010 Battery pack” on page 67
• “1020 ExpressCard blank bezel” on page 68
• “1050 DIMM slot cover” on page 73
• “1070 PCI Express Mini Card for wireless WAN” on page 75
• “1080 Keyboard” on page 77
• “1110 PCI Express Mini Card for wireless LAN” on page 85
• “1120 Keyboard bezel assembly, FPC cable, and Bluethooth daughter card” on page 87
• “1150 Speaker assembly” on page 95
• “1160 LCD unit” on page 97
I had many laptops and I can say that the accessing the fan assembly was far easier in non-thinkpad ones. I like to clean the fans by directly accessing them, a gust of compressed air cleaning it is wishful thinking.