For some reason I've never gotten into Sega's consoles. Sure I've played Sonic, but that's about it. However, when I heard about Sega Forever, I thought I might give it a try - watch a few ads, play a few games. But now I probably won't bother.
The question for me is why Sega would release anything less than perfect. I have to conclude the decision makers at Sega don't care about their games, only about making money. Not to say that making money isn't important for a company, but I suspect Sega Forever will make less money than if they spent more money to release a better product. Instead of engaging players so they play more, and thus watch more ads, this poor product (with apparently heavy advertising) is more likely to turn players off - resulting in higher short term gains, but very little long term returns.
I also suspect the difficulty of emulating consoles is not appreciated. The primitive CPUs and GPUs were tightly coupled and many games exploited this via cycle counting techniques. Reproducing this relationship, especially in devices which can vary considerably. Plus there's no easy way to "scale down" for lower performance devices.