I think the problem is mostly money to begin with. Nintendo cannot just put them up for everyone to buy. Lots of legal stuff. I mean look at all the PS1 games that were brought over to PSN, not too many, because it is a complicated legal matter.
I remember TOMBA 1 and 2. It was an independent publisher that brought it to psn and it took them years to do so. Now imagine if they dont even know if it is worth the trouble and nobody is going to buy it? lots of money wasted.
But I think it would be amazing to have all these old games available :)
True but they can do as they please with their own IPs. Really all of the IP owners need to come together and put these up in whatever online store they need to be in. It is not just Nintendo in that regard for certain.