You're saying I should go to an authorized Apple shop and have them crack it open to dust it out and change thermal paste?
I've always had Thinkpads and Dells which are servicable, and I do spray compressed air on the inside every few years, but have never re-applied thermal paste.
You do this on your MBPs? How much will it cost every few years, and also should I bother with Apple care? Right now I've only the one year warranty.
As for the MBP 2015, many users have reported that the thermal paste Apple puts in it in the factory is not optimal and they achieved 4-7 degress less sustained temperature by using a better one. I am attempting to do that soon.
As for air sprays, DEFINITELY DO NOT THAT. MacBooks are crazy packed on the inside, it's very risky in my opinion. Cleaning it from dust once or twice a year is extremely cheap around here in Bulgaria -- they charge me 20 EUR if they are grumpy. (Mine is out of warranty however, I bought it refurbished from a colleague.) Authorized Apple shops might charge times more though, I haven't asked and I don't know.
And finally, replacing the thermal paste is also an extremely quick process. A good technician does it for 30 to 45 minutes and a paste costing no more than 20-25 EUR can be at the top of its game for 2 years or more, depending on usage.
All in all, I plan to de-dust the laptop in a service shop once a year, and change thermal paste if I notice an increased sustained temperature. (Definitely buy iStat Menus, it gives you tons of diagnostic info right on your menu bar.)
Hope that helps.
As for the builtin software's quality, I agree it's not stellar -- and the App Store on macOS is a relic from the past that's way beyond its lifetime and needs urgent rework.
That being said, the OS itself is crazy stable for me and the occasional glitches appear only once or twice. Not sure how you got so unlucky, sorry about that.
And finally, I was able to find software for absolutely everything I need, in every single user or programming area. Granted I am not a researcher that has to maintain 50+ installed runtimes and compilers but I code in several languages and use several different databases and I haven't stumbled upon a single issue there.
I am gathering money to buy the maxed out iMac Pro (~$13,100) but in the meantime I have nothing bad to say about the MBP 2015. Occasional stupid bugs do occur of course, like in any OS, but rarer than on my Windows 10 PC, and a restart fixes things which usually never resurface again.
So yes they are expensive. I was a Linux/Windows and Android advocate most of my life but eventually conceded that Apple is simply much more comfortable, predictable and ergonomic (their displays don't tire my eyes as any other display I tried, including gaming displays with 144-200Hz refresh rate) and that I have better things to do with my life than to always do the OS authors' work for them. Much bonus points to them for actual privacy as well.