I don't understand the thought process of companies bringing guns like this to market.
A roller locked, stamped steel rifle is an evolutionary dead end, so it will never be a contemporary solution. It will always be outclassed by more modern offerings. So, that leaves the 'I want an HK G41, but they are unattainable' crowd, and the 'Oooh, neat, it's not an AR15' crowd. They've alienated the 'I want a G41' group by putting an AR15 grip and a welded rail on it, so their entire investment in this platform is riding on the 'Oooh, neat, it's not an AR' group. I don't think this will be sustainable for them.
Factory HK grip housings that are compatible with the mounting scheme on the G41 are available, but they share architecture with the 21e and 23e, and sell for over a thousand dollars (I'm not aware of any that are US made, but maybe there are). Even so, these would need to be modified to fit, and only a few would risk hacking up a $1,000 grip housing to make a clone.
Sig used this same formula when bringing the 550 to the US market: Make a retro gun that people want, but try to make it as much like an AR15 as possible. Unsurprisingly, it didn't work out.
I think they would sell a few more if they made something that could be a better starting point for a decent G41 clone.