Retarded is a very very stupid way to brand these. I'm sensing it's because they're not mainstream products they are regarded as second rate.
There are a lot of consoles which really did miss the boat. The GX4000 being the biggest miss I can think of. This was Amstrad's failed attempt to access the console market (based on the CPC6128) but releasing an 8 bit console up against the mighty 16 bit Sega Megadrive pretty much killed their mission before it started.
However, that was when the industry had found it's feet (hence it being a miss). When the video game industry was in its infancy everyone was feeling their way with a brand new technology. Some have to win, some have to lose, but none should be regarded as 'retarded'.