False on both counts.
Both Apple and Miele offer Self Service Repair.
Specifically in the case of Miele (since its the subject of this thread), you can buy spares directly from Miele. They openly show exploded parts diagrams on their website, and if you can't find it, you can call their parts sales number.
With the caveat that the prices are ridiculously high to encourage you to just buy a new one. My brand new Miele C3 vacuum cost 300 EUR and I just checked the official spare parts store you mentioned. Replacement handle is 90 EUR (not including the telescopic pipe, that's another 80 EUR, or hose, that's another 40 EUR), cable reel is 100 EUR, new motor is also 100 EUR, top plastic cover (which can't cost more than 5 EUR manufactured and delivered) costs 50 EUR, and so on.
The instant they stop selling a model, all the documentation is thoroughly whisked away and inaccessible to customers or anyone a customer can reach.
And they never gave me that kind of documentation so it’s not even something I “should have” saved myself.