Latest OS4 lacks fundamental features that both developers and users expect to find in an OS today. Noone outside the Amiga community is interested, and the few who might be, quickly shun off once they see what state the OS is in.
Sorry, but I don't agree here, Ok, there's no memory protection, there's no multi-user architecture, no Posix and no "whatever fancy feature you feel a question of life & death", but I don't think average people will ever list OS features and decide what to buy.
They will, instead, ask basic questions like "will this make me surf the web without issues? will this allow me playing my videos? will this hel me with my every-day duties?" and so on. You can positively answer to all these questions even without such "modern" features, but providing the necessary applications.
I can agree, however, on the gaming issues: the isn't a modern and consolidated hardware 3D-accelerated API architecture in AmigaOSes, and this IS a show-stop issue. On the AROS side Deadwood is busy porting Gallium3D: maybe it would be a good idea if people form other Amiga dialects would join the effort and help to create a common 3D baseline for the whole platform.