I think if you look at the strides F1 has made in the last couple of years it is definitely possible. The US is a neglected market, as is much of central and northern Europe. The sport doesn't need a consumer market in the traditional sense to be a successful entertainment product.
My point regarding the TV series is not so much that I am bothered by the lack of native English speakers personally (big fan of international cinema), but more so that it betrays the fact that MotoGP is absolutely not an international sport. Dorna is and always has been way too focused on the territories it understands and never had much success in expanding the product much further afield (with the baked in fanbases of the east a given). Having riders and tracks from other countries always helps, but the events are still quite niche and are not promoted with any real mainstream focus.
Although not directly relevant I think the expansion of the UFC internationally proves that even historically unpopular sports can gain a decent sized following and turn a great profit if the entertainment product is cheap to attend and widely televised without prohibitive cost attached. I am a season pass subscriber and the cost is quite frankly a joke. I share it with 3 friends and it is still deemed expensive, and it doesn't even include access to WSBK races despite Dorna holding rights to both championships. Plain greedy.
Dorna needs to do far more to support and expand feeder series across the globe, or at the very least provide a more accessible environment to riders from other series such as those that are supersport based. The fact those riders historically have been uncompetitive is the promoter and regulatory bodies problem to solve. In addition more needs to be done to create a more cohesive approach to the entertainment package. Little tech features on YouTube with Crafar are never going to work, and the E sports side of things is woefully under developed.
All in all I think Dorna has done a terrible job outside of its native Spain and neighbouring Italy. The on track show is the best form of motorsport on the planet in my opinion and they have done little but profiteer, when a truly visionary promoter could fairly easily widen the sports appeal. The fact that people regularly ask me how Rossi is getting on or if he still races, proves a single man did more to promote the sport indirectly through his own self interest, than Dorna has been able to achieve in that time, and with a decently sized budget. If anything, that should be viewed as a huge embarrassment and major failure for a business whose job it is to promote a sport.
Is F1 really comparable to any other race series? I'd say no. Merc has spent 1.2B+ over the last few years. There is zero equivalence, nor anything to learn there.
The USA is a unique market with their own, traditional, series and very limited interest in non-american sporting events (soccer, F1, MGP don't do as well in the USA for a reason).
I see very limited appeal for MGP as an "entertainment product" without prior interest.
I totally fail to understand your point that participants from a wide range of countries, speaking a wide range languages means that MGP is NOT an international sport, unless you are solely focused on MotoGP. In the lower classes, often watched as much, if not more than MotoGP itself by my SE Asian friends, they love hearing Thai, Bahasa Malay, and Bahasa Indo. The biggest future markets use small bikes, watch small bike racing and buy Repsol branded 150s. The sport is FAR from niche here.
Fight sport is an extremely poor comparison. You seem to fail to understand that fight sports DO have international, universal appeal, racing sports do not.
Dorna should most definitely not be trying to fund global feeder series. It would be impossible. And there is so much grass-roots racing of small cc bikes in developing countries it is totally unnecessary. What is required, as you mentioned, is a path to MGP for promising stars, Reza and Idemetsu have invested in this.
One thing always overlooked when judging the competitiveness of racers from where I'm from (equatorial region) is the geographic and cultural adjustments necessary along with the adjustments every non-equitorial rider must make when moving up classes. Subjective example: Wilairot was always slow after lunch in his first year in Europe - he was used to a traditional large lunch followed by rest in the heat of the afternoon. Taking riders from non-euro climates and geographies takes additional adjustments.
Currently I am preferring the on-track show of the S1GP championship to MGP.
https://www.supermotos1gp.com/
