Let me explain why I don't like Steam ...
It is 3rd party software that I am forced to have installed and running to play a game. If an extra program is running, that is taking up RAM and CPU which could be used to make the game run better.
That's not really how it works. Sure it uses some RAM (around 50MB...this firefox window is using 300MB as a comparison) while sitting there but the that's all it basically does - sits there waiting on you checking the store or launching a game. RAM-wise it's nothing at all as just about everyone already has far too much RAM. CPU-wise it is a very tiny amount and you probably have a couple of cores sitting around doing nothing much anyway.
The performance overhead from something like Steam is negligible to the point of it hardly being worth consideration at all.
Am I against change? against downloading games rather than buying them off the shelf? Not at all. I actually like Good Old Games.com very much. Buy my game, download it, install it, play it. No 3rd party software needed to be running to play my game. If I want to re-install my game, I just download it again from GoG.com.
So if I have a choice between GoG.com and Steam ... I'll choose GoG.com everytime. How people cannot see that having Steam running so you can play a game is not a good thing, really baffles me.
I like GoG as well but Steam is pretty ok too. Actually to be frank the Steam program is a piece of garbage - one of the worst programmed bits of software I've ever had the displeasure to use - but I still use it because its nice to have that one place where your games are kept. Also the prices are unbeatable, hard to argue with that.
Lastly ... "I am not daft enough to fight against it just for the principle" "I don't like Steam having a monopoly myself but I use it for everything now" These are not good statements. Trust me on something, Elite: Dangerous does not need Steam, it's more the other way around.
Steam doesn't really have a monopoly - there are plenty of big guns out there who can put out a lot of big game on their own platforms. The biggest issue so far is that they've mostly been awful (EA's Origin and that horrific Uplay crap). GoG is out there now and more keep appearing. Yes Valve is in a good position but they are being attacked from all angles by some very large corporations.
Elite is a game capable of sales in the multiple millions, but it won't happen without Steam. Steam doesn't need the game at all.