Look it's all about the 'right to repair' which Apple have completely locked downApple under Steve Jobs never intended those to be user repairable. The only thing that Apple allowed was the accessible RAM slot on the early aluminum iMacs. The trend was already there with Jobs. Compare those to the plastic or non unibody MacBooks which have easily accessible drives, RAM, and battery. Heck, Jobs brought us the MacBook Air, and literally said that is the notebook of the future, slim, unibody, almost no ports, and no user accessible parts. Don’t be in denial.
https://www.apple.com/uk/legal/sales-support/terms/repair/generalservice/servicetermsen/
Go to an Apple Genius Bar with a faulty MacBook Pro and you will almost certainly be told it needs a new logic board even if it doesn't and if it does only Apple can fit it.
You can only use Apple parts which is extortion given what they cost when quality third party parts are available at a fraction of the cost.
Apple RAM is extortion and on a Late 2015 21.5" 4k iMac the RAM is not only soldered in but it has a 5400rpm HDD which is just unacceptable.