You might be right in terms Serie A, but then I don't think Serie A is very marketable now either. La Liga can sell itself on Real and Barca plus maybe capitalise on the fact it can be the default European league for the Spanish-speaking world. Bundesliga arguably has less really iconic clubs than the Prem, at least ones that're currently really competitive. Old established teams like Man U, Liverpool and Arsenal speak for themselves but Man C and Chelsea now have a huge presence in Africa thanks to the Prem getting in earlier via tv than anyone else and to high profile Aftican players here. I'm sure there are equivalent players in the Bundesliga (as there obviously are in other leagues) but from what I understand fans there are obsessively loyal and it'd take a lot to shake their loyalties to whichever club they've adopted. One of my work colleagues is from Nigeria. He knows more about Chelsea than any English fan I've ever met, and easily as passionate about them.
Read this. It's amazing!
Obviously there's more to the world than Africa but assuming latin America is more likely to go La Liga that really just leaves the US and Asia. Maybe the Bundesliga can make inroads there. I'm not sure how big the Prem is in either. And Europe, obviously, but Europe obviously has its own individual domestic leagues dominating.
Another potential problem is the stylistic similarities between the Prem and the Bundesliga. If people are subscribing to the Prem for a certain style of football, will they also be willing to pay for a slightly less high profile variation on the same thing - especially given the likely influx of even more superstar players in the next few seasons.