Even Nintendo doesn't really get it right. Controllers have short cords, the aspect ratio and colors can be off, short supply, etc.
The thing that helps Nintendo the most is nostalgia, presentation and their strong 1st party games. A lot of the other companies that have tried don't own as many properties, so they get the games that don't have high royalties. Also, emulation software isn't as strong because they're not as popular. Besides that, most of these retro knockoffs are pretty much the same as the NES/SNES Classic.