Supporting the 1% of Linux gamers is important now because it's really difficult to imagine a scenario where Windows gaming remains the status quo twenty years into the future. Preparing for what I'd certainly argue to be inevitable is important and frankly it's just weird to have support for Linux titles for sale but not support a client to actually download those games and take advantage of all the features like cloud saving?
Its simply money, they are scraping along with the businessmodel they use. Of course the future isn't bright with the advent of streaming and the plattform gaining more and more importance over the actual hardware thus leading to big studios buying smaller studios in order to rise attractiveness for their plattform through exclusives.
Thats why gog is trying to go the route they are takeing as they fear they will just get crushed if the players on the market with a lot of cash are starting to by up the market so the competition won't get it.
Among enthusiasts I find that the sentiment towards Windows is overwhelmingly "I use it out of necessity but once I don't feel like it's necessary anymore, I'll move over"
What enthusiasts are you exactly talking about ? Those that gripe over Windows 10 ? Saying those things is something completly different than actually doing things - think back at the outcries when online activation was trickling into the market, with tons of people stating that they would never support that - now its common business practice. Or how many people said they would never support the Epic store, and now they have an account because there is this one exclusive they "need" to play. And this list goes on and on
and personally, that date is quickly approaching as almost every single game I play is 100% playable through Linux thanks to DXVK/WINE/Proton or native ports. If Valve is essentially financing the success of Linux' gaming, why not piggyback off that success?
Thats the problem with anecdotes: I made an effortv recently trying to get things running with lutris and it totally failed, out of 20 games I tried i got 15 running properly on my system with six or seven needing several manual steps to get it working properly. That does not mean your experience is invalid, but that you can shave off probably a third of the already small number of active Linux only players where your experience is the norm.
Not to mention I bet the overlap of people who are staunchly anti-DRM (GOG users) and the people who care about Microsoft's stranglehold over PC gaming is pretty high. It's the #1 requested feature for Galaxy and a day doesn't go by that it isn't asked about by ten different people.
But hte number of those people is rather low, and I highly doubt that 10 different people would ask for it on a daily basis (I would argue that even gogs userbase isn't growing by that number every day).
If the community is the one maintaining a Linux client, what is there to lose? They're already selling the games so they're already dealing with providing customer service for those users.
Because if gog is connected to it, people will think that gog is responsible and will ask for support and will get angry if gog would refuse and say "its open source ask the people that made that". I did voluntary support for an open hardware/software project for several years and most of the time I had support requests from people that where using a similar named internet service, with a not so low number of people getting angry because I did not want to help them although I wrote that the project was something completly different.
Put Linux aside, what is there to lose by open sourcing the client itself? There are many talented people in the community that would love to implement a big picture mode for example but they can't because they don't have access to the source. Open sourcing equals more features, better security and it's all done for free and maintained by the community.
Yes there are many talented people out there doing a lot of great work for free. But those people often leave again after some time (changes in their real lives, loose interest etc.) and leave what they made behind (and if you are really versed in the open source software landscape you will surely come across a lot of lighthouse projects where the community made a great pice of software that still thrives, but you will also have seen mountains of project that where started with great effort and died even before they had something to release). This may be the best documented and structured code that is totally modular ever created, but it can also be hot mess of "codeblobs" that may be a stroke of genious but are not maintainable and integrateable into the codebase gog uses.
And as gog bases part of its business strategy on this, this thing needs to work, they need a reliable codebase - which simply isn't easy to keep even inside a company, let alone with contributers from outside. Which you need to "take care of" as they may not take it very well if their input is rejected or can't be dealt with in a timely fashion. Which needs people that communicate that properly as programmers often as not don't have time and/or the social skills to do that > again money needs to be spend.
And as said before just having official and unoffical builds won't get you of the support-hook and leave the possibilty that the community just runs with it, in the end leaving gog out of the picture, by "declassifiyng" gog through makeing it just another integration and not the main focus anymore.