Read the thread entirely. The aosp devs have stated they are not buying the s4. Doesn't look good, at least for now. They say developing for them will be a nightmare and not worth it. Im honestly shocked.
I'm not. Samsung has basically co-opted a bunch of Google services, trying to make it their own. Android's ecosystem is built around Google, and Google has been incredibly friendly to developers. Developers recognize that freedom. They do not want to give their labor to projects that may be moving away from Android and Google's ecosystem, not to mention app developers do not want yet another platform to develop for.
My sympathies lie with the developers. Samsung basically wants to cut Google out of the revenue model - they want to use Google's revenue model with services, but they want to provide the services, pocketing the money from the revenue. Android developers don't want to support that, and good on them.
The majority of the buyers of the SGS4 could care less about roms, and rooting, so I see this as no big loss.
The importance of the developer community does not necessarily lie in direct sales. But developer loyalty to brands matter. Why? Because if developers develop new features and smoother running versions of the Android OS on your phone, the manufacturer can profit from including some of those innovations in their future phones without having to do any of the hard work themselves. Samsung gained developer loyalty by making developer friendly phones. But they can lose it just as easily if developers view them as trying to create a crack in the Android ecosystem for their own profit. Samsung's success is at least partly due to developer support.
Don't forget that developers also have a big say over much of the tech press.
Yes, the S4 will sell "millions." But the question is, will the developer snub hurt their overall image, and eventually, numbers? I think it will.