They are almost the same internally, similar processors, similar batteries, similar GPU/memory, PCH, etc.
>My retina MacBook pro overheated and needed a paste replacement and fan cleaning
This should be rather trivial job - likely 25-30mins if you have the pentalobe screwdriver.
Even though Thinkpads like the old xx20 and xx30 series require more parts to come off, they are easier and faster to replace the thermal paste on. Nothing feels as awfully stuck, overengineered and way too small as on the Macbook. Newer business Notebooks from Lelnovo and Dell are even better with that.
I am in no way defending Apple's policies that are openly hostile to repair and maintenance, yet I'd expect most people to be able to open a Mac, if they read a guide/watch a video and they have the correct tools.
I do maintain/install/repair most of stuff home - the worst offenders are the ones that consider epoxy a viable engineering tool for fastening. Macs at least don't do that... yet. Also they don't contain built-in mechanical points of failure (printers are notoriously bad when it comes to weak springs and certain plastic gears; I don't consider having too short flex cable 'mechanical')
This is already a problem - what's the reason they couldn't use a standard screw beyond making it intentionally more difficult to repair?
Screws are still relatively tame and easy to work around but I'm sure if they could come up with some smart, DRM-powered screw that only an official, Apple screwdriver could open (after an online check) they'd do it.
I'd guess the 1st pentalobe screwdrivers are machined initially.