Well considering how the Star Fox series is almost dead, I'd imagine Nintendo themselves will make the next one to try and revive it. Because I'm sure Nintendo is not happy with how downhill the series has gone.
Star Fox - 2.99 million worlwide
Star Fox 64 - 4.03 million worldwide
Star Fox Adventure - 1.85 million worldwide
Star Fox Assault - Last time I saw anything it was around 500,000 maybe more worldwide
Star Fox Command - This one I have no real idea. I think it did 100,000 it's first month in America and then dropped and in Japan I think it was close to 100,000. No idea about Europe but considering the series was usually most popular in America and then Japan, I'm guessing Europe sales wont add much.
So as you can see the series has gone from a huge sales franchise with Star Fox 64 into a small niche with Command. In order for the series to become popular again something major needs to be done and I'm sure Nintendo knows now that they are the only ones that can do it.
Because if it gets farmed out to one more third party then we can consider the Star Fox series offically dead because it would say Nintendo doesn't even care about the series anymore.