- Home console and handhelds were still separate to the benefit of both.
I would say that merging the two was definitely helpful, at least in terms of maintaining a viable development platform for both. Nintendo's portable devices have always sold well, but sales of their consoles had been increasingly lagging behind the competition, with the only real exception being the Wii, which managed to attract a much wider audience. As far as worldwide console sales went, the NES sold around 62M units, the SNES around 49M, the N64 around 33M, and the GameCube around 22M, so there was already a downward trend in sales numbers for their consoles prior to the Wii, despite the gaming market itself expanding greatly during that time. The Wii changed that trend with around 102M units sold, as it was able to appeal to a wider audience, but then the Wii U went back down the route of decreasing sales from where they had been prior to the Wii, with less than 14M units sold worldwide. Nintendo failed to convince the wider audience they attracted with the Wii to buy a Wii U, and it seems unlikely that another dedicated console would have done much better, short of it being another unique hit like the Wii. And without having a critical mass of consoles out there, few developers will put much effort into developing for the platform.
Their portable devices, on the other hand, have sold very well, leading the market for dedicated gaming devices by a wide margin. As far as the numbers go, Game Boy sold around 119M units, GBA around 82M, DS around 154M, and 3DS around 76M. Though while the numbers for the 3DS where still very good, even they showed a reduction in sales, likely mostly down to increased competition from smartphones and tablets. Another compact dedicated handheld would have likely sold well, but may not have reversed that downward trend. But by combining the portable device with the console, they were able to maintain a large install base for both, which in turn garnered them good support among third-party developers. Sure, having a more compact portable device and a separate more powerful console might be nice, but if one or both of them don't manage to sell, then they are probably not going to be well-supported either. At 136M+ units sold for the Switch so far, Nintendo likely made the right decision with combining the two.
- They put Metroid Prime Trilogy on the eShop for $20.
While that might have been great, what they did with the original release of the Prime Trilogy on the Wii was not all that consumer-friendly. That release was widely acclaimed, but it was only in stores for a few months before they discontinued it, which when combined with the fact that there was no digital release, meant you could not play the best version of those games updated with improved Wii controls at all, short of buying some massively overpriced used copy, at least until they were eventually re-released on the Wii U.
Wii online multiplayer for most games ended over a year after the launch of the Wii U in 2012, and the Shop Channel didn't close until 2019.
They might have kept the shop around for a while, but WiiConnect24 functionality was ended within months of the Wii U's launch, which removed a number of services like news, weather, voting, the message board, and more importantly some game functionality like the ability to see other user's created Mii characters randomly appear in certain games like Wii Sports Resort, or the ability to challenge ghost runs in Mario Kart, among other things. And discontinuing online multiplayer entirely for all of their games a little over a year after the new console came out was even worse. These were their popular first-party releases that sold millions of copies and helped sell their hugely successful platform, making it absurd that online multiplayer functionality would be discontinued so early after the next generation of hardware came out. Again, that sort of thing reflected very poorly on their perceived long-term support for their platforms, and in turn only hurt their ability to sell the Wii U.
The GBA was a definite change in hardware that was able to run GBC/GB. Nintendo considered it a full successor, with unique hardware that had compatibility because the GBA just had the GBC CPU as a CoPro(used for 4 of the 6 sound channels) . The GBC was just a memory and CPU clock boost. The DS' backwards compatibility was like the GBA, they jut included a GBA CPU as the DS's copro DSi & New 3DS are pretty much the same as the GBC being just spec bumps, with limited exclusive games. accoding to Nintendo their generations go GB->GBA->DS->3DS->(switch? they count htat a home console, but we'll see if that holds true in the future. Seems like they were doing what they did with the DS calling it a 3rd console that didnt competeing with the handled N3DS, like the DS wasnt supposed to be a GBA sucessor, until it was cleaer the DS was a sucess. Then they did start reffering the the DS as the GBA sucessor. Now that the 3DS line is dead and the Switch is very popular they might change their tune. Guess it really depends on if they decided to release a second device that fills either the console or handheld role)
While I would largely agree, the Game Boy Color was a bit of an odd semi-generation in that there were a couple hundred or so game cartridges released for it that would only run on the hardware, and were not backward compatible with the original Game Boy. And it's pretty clear that the Switch is more of a portable device with a dock than it is a console, and it was clearly marketed as serving both use-cases, so it can be considered a successor to both the Wii U and the 3DS. I can't really see Nintendo going back to separate console/handheld devices any time soon, though there's the possibility of them offering something like "mini" and "HD" versions of the same device geared more toward one use-case or the other. A second, completely separate device with it's own game library might only happen if they were to release something totally different like a standalone VR-headset.