I didn't mean that Ubisoft's was better than Steam - just better than Epic's store when comparing both against Steam. I hated the uPlay store as much as everyone else.

As for your question, once you have feature parity, it becomes about finding a niche. GoG has its list of old games and lack DRM going for it, for example. Nobody is going to pull large groups of people from Steam immediately without some major draw, obviously, but if you offer a similar service that doesn't exclude people on other platforms like Steam from playing games with people on your own platform, then people will be drawn to whichever they like better.

The big reason I think we don't see any real competition for Steam is that the companies with the funding to do so all wanted to force a piece of the pie rather than actually compete with Steam on quality of service. If EA, Ubisoft, and Epic had tried that, we would probably have a much more diverse ecosystem of storefronts - especially with crossplay becoming common. As it stands, Steam's biggest competitors are the consoles, and that's largely down to hardware preference rather than storefront/launcher preference.

Steam has so much impetus now that competing with them is very difficult, but as I saw somebody else in here say, if Epic had done something like offer their lower take from devs on sales at the agreement of a 5% lower price on their platform instead of spending all that money on forced exclusivity, people would have a real reason to go there instead of Steam (if the quality of service were comparable).