I wouldn't be too concerned about no dealer network in the US market. 75% of the "current" GasGas dealer are not going to be able join KTM (or want to) due to the KTM business model. So within time when Rieju is ready, you will see some good dealers become Rieju dealers.
Rieju is already working on a few of the "updates" to the platform. Trust me, i think they were probably bombarded by many distributors across the globe about some of the minor issues to a great bike. Issues that GG never really addressed due to mismanagement and lack of R&D funding.
Plus there might be a few new tricks up Rieju's sleeve. Time will tell, its early yet, but expect 2021 models by mid to late summer in the US.....by someone.