The 5.2 Billion is in Canada where the population is around 36 million, a Six Nations tv deal would definitely not command that money but it could command a lot more than it is right now.
Romania has a population of roughly 20 million, Georgia is 4.5 million. The reason these countries don't generate much interest in Rugby is because their teams don't ever get to play against top competition. In fact, this really only applies to Romania, Georgia draws excellent crowds for all their rugby matches. A match against a Six Nations country would probably sell out the national stadium 50,000+ as Georgia is a rugby mad country. Romanian rugby also influences rugby in surrounding countries in the Balkans and Moldova so you've got those countries which could be targeted as well.
Romania has hosted tonnes of highly attended tests in the past. Of course the civil war in 90s did a number on their rugby but they are slowly recovering.
Romania and Georgia are so much better than the other participants in the ENC, Georgia is probably as good if not better than Italy and they regularly beat them at age grade. Romania aren't far off the Italians either. Short term the plan should be to expand the Six Nations to include Romania and Georgia.
The same arguments being made against this were used when it was expanded to include first France and now Italy, including these teams has only enhanced the competition. Long term the plan should be to put promotion/relegation in place between ENC Div 1 and a new Eight Nations tournament as that would bring Spain, Portugal, Germany, Russia, etc... In to the fold. This would make the 6N the de facto European Championship.