but I don't think you actually lose customer if your DRM are well done.
In my view - no DRM can be well done, and some customers always will avoid DRMed services. So Steam loses some customers for sure. Many of them end up as GOG's customers naturally ;) Competing on DRM-free as a feature has its benefits.
Is this really true, or we suffering from Pauline-Kael syndrome here? How many people are actually aware of DRM outside of a rabid internet minority (and I include myself in that list)? It may lose some customers, but I bet its a minuscule fraction.
I mean when you buy a disk, put it into your PC, and can't play it because there's no internet connection. Or when your internet cuts out and your game quits even if you're not playing online, just because the DRM can't phone home anymore.
Is it true that people who dislike DRM prefer GOG over Steam and that DRM-free is one of the primary features that attracts many users to GOG? Yes, it is true. How many - I can't say exactly, but this subject is often brought up on GOG forums and site features feedback - you can read about it. Minority or not, GOG responds to this demand, while Steam doesn't, so GOG is more competitive in this particular aspect.
I don't doubt that - I've bought games on both platforms (Alpha Centauri on GOG = awesome). But the point is, amongst total games sales, I would like some degree of proof as to what the actual effect of the outrage is. Of course the GOG forums are DRM-angsty; that's part of why they are at GOG! What I don't know (truly - not being adversarial here) is whether DRM is a real factor for a substantial number of buying decisions, or not. The recent Sim City fiasco was probably the highest profile DRM-related brouhaha ever; - Rock Paper ShotGun, QT3, Polygon, all the gaming press (including the larger offline press like PC Gamer) covered it and expressed outrage, as did some mainstream media. And yet, best as I can tell it had little effect on actual sales (I'm open to being convinced I'm wrong on this).
What I don't know (truly - not being adversarial here) is whether DRM is a real factor for a substantial number of buying decisions, or not.
I'd be interested if someone could make a thorough research on these decision factors, but I'm really not sure what kind of methodology can be used for that. It's hard to measure such things for external researchers. Companies which participated in DRM fiascos (like the SimCity one) probably can estimate how many customers they lost in result, but they might not want to publish that information :)
Ironically though, lost sales caused by DRM won't necessarily make them change their minds about DRM. Some publishers executives can excuse failures of their low quality products by lost sales caused by piracy, so they use DRM to cover up their incompetence (i.e. "we are doing all we can!"). So additional lost sales won't convince them to drop that excuse for their products which fail just because there is no big demand for them. They'll claim it's because DRM wasn't yet strong enough, and pirates just cut their profits ;)
In my view - no DRM can be well done, and some customers always will avoid DRMed services. So Steam loses some customers for sure. Many of them end up as GOG's customers naturally ;) Competing on DRM-free as a feature has its benefits.