Most recently increases are probably mainly due to cloud services, WSL and partnerships like the Dell and Lenovo ones, but the feeling of dedicated 'contributors for a cause' is still there. WSL may convince a set of users to stay on windows instead of converting, but it makes Linux more known and more used and that will only make the number of users increase at first. Long term, it is hard to predict.
Linux on the desktop is now around 1-2% by some estimates. I don't think it will ever reach the market share of windows, I don't think it will even reach the market share of the 'previous windows release', but it may grow still. If it reaches something similar to MacOS, maybe 10% 15%, hardware vendors and service providers won't be able to ignore it anymore and that will bring a new cycle of adoption. After that, it will stabilize, but at what point is also not easy to predict.
As whole, FLOSS is getting good enough in most aspects and needs. It doesn't needs to be 'the best' or 'the favorite among professionals', amateurs doing something outnumber professionals in most areas. Inkscape got good enough, audacity (or what ever fork replaces it) got good enough, krita and blender got good enough even among professionals, Libreoffice is good enough if you don't have to handle MSO-born documents. The situation continues to improve and gimp 3.0 will be better, 3.2 will likely be good enough even for professional photographers. The landscape seems for video amateurs, animators musicians...
Around a decade ago, Linux on the desktop was adrift. Now, there are routes which will take some time to mature but seems like good bets: PipeWire will bring good enough latency like jack with the same features of PulseAudio for audio AND video; snaps took centralized software distribution, Flatpak took decentralized software distribution and AppImages took direct distribution... that alone made software distribution on linux much better; Wayland will fix remaining Xorg problems... Oomd will fix lockups when out of memory... Wherever there were serious problems, now there is a route.
So, things are going in the direction of 'good enough' soon for the general case and most niche cases too. For me, it has been good enough for more than a decade.