but the avs exists so how's it not possible to have it as a product then?
Look on eBay, people want between $90 and $160 for original model NES systems.
The AVS is $170 and only does 720p, the NT Mini is $450 and does 1080p
AVS: Xilnix Spartan 6 (about $18)
NT Mini: Altera Cyclone V (about $50)
The NT Mini also has two simultaneous outputs, HDMI and RGB/SCART/SVIDEO/Composite.
As I mentioned earlier for a FPGA-SNES, just the exact-same FGPA on the $600 development board is $426 alone. So we don't know what the minimum FPGA needed is yet. If we want a model that can just read a SD-card with games on it, that would require a much more expensive FPGA to emulate all the expansion chips. It's still too early to determine what can be built.
The people who built the AVS and the NT Mini are addressing the part of the gaming market that desires preserving the accuracy and ability to play the original cartridges. The NT Mini additionally has utility as a competitive gaming/streaming device due to having two outputs. Likewise it allows people to not have to risk losing/destroying their original NES.
I'm absolutely sure if the cost can be narrowed down, someone could kickstart a project to build a few prototypes using new-old-stock SNES parts, and an overpowered FPGA to leave some headroom for fixing bugs, and then when all the games have been tested a cheaper model could be built using the prototypes. But I don't expect a $200 FPGA-SNES.
We are getting too ahead of ourselves. It's very likely Nintendo will produce a "SNES classic" like they did with their NES classic, which are just software-emulators (like the Retron 5 or Retro Freak) and that may increase interest in playing SNES games authentically, or maybe people will just settle for the less-accurate-but-cheap product from Nintendo. A lot of interest in emulating the NES accurately is because the NES emulation on the Wii/WiiU color is actually poor on the TV (but OK on the WiiU controller.)