I do not mean to be contrarian, but i just don't agree.
I think you'd find that NES games do exceed the 8 sprites per scanline "limit" more often than not. If games always heeded what looked good*, the spectrum of viable, interesting game designs would shrink quite rapidly. Remember that the so-called limit is a soft one. Technically speaking, you can put all 64 sprites on the same y coord on the NES just as you can on the AVS. The design value is very questionable, but you still can.
Or would you call bubble bobble not fundamentally grounded to any real system just because the designers chose gameplay design over visual presentation, and the AVS happens to do a better job displaying it?
*i'd also argue that "looks good" has different connotations among homebrewers and the predeceding demo scene than it had for commercial NES developers of the day. It seems to me this is a value passed on from hacker culture and the demo scene where writing "elegant" software is valued, whereas being pragmatic was mission critical to those who designed or wrote games back then.
Secondly, the AVS is not an imaginary system. it is very much real in itself, and any game that would be running on the AVS is 100% backwards compatible with the NES.
Lastly, if we were going to draw lines on what's fundamentally grounded or not, every cartridge type except an NROM one is a cheat since it does things the console can't (mappers do what nintendon't).
Mapper 30, which NESmaker relies on, isn't historically accurate (or even historically present), so if we were to draw such a line, not a single game made with NESmaker would be "fundamentally grounded to any real system".
The bottom line is it doesn't matter. The NES is, among other things, an interface to your game. I'm honestly more interested in the NES seen as an interesting, specific interface to entertainment, experience and fun, than the NES as a nostalgia catalyst. Everybody probably feels different about what is important to them, but the good news is it all fits under the umbrella of homebrew hobbyism.