Even let's say BCCI agrees to send some players into this league, they won't be capped or contracted players and the main issue would be sustainability (schedule is another obstacle) despite Saudis having deep pockets.
I don't think that sustainability is a concern for the Saudis. They brought Cristiano Ronaldo to their country by paying a massive amount. They know that it will be impossible to get returns of even half of that amount. What they want is publicity and acceptance among the global community. At this point, they are not focusing on revenues or sustainability. And once again, the BCCI will not send any of the active players to this tournament (irrespective of whether they are capped or not). They don't have any reason to do otherwise.
That's not the case with cricket, where only one country generates eyeballs. I fail to understand why people avoid connecting the dots of ICC media rights in this context, it's in front of everyone still no one considering it. The rest of the cricketing world not paying money to watch ICC tournaments and somehow people think that they will watch random t-20 leagues.