>I am not too bothered about them needing to do more work given that they produce a premium product, in fact putting more care in is their entire shtick!

Putting more care in the LATEST offering. Putting more care in older versions if a loosing proposition.

And it's not just a "throw more people / money at it" problem. After some point the complexity of legacy support grows exponentially and the code suffers (or gets hold back).

>Car makers don't stop making spare parts a couple of years after a new model comes out. If they did no one would buy them.

5 years in computing is like 20 car years...