This is the the new model, IMHO. Getting quality content for the media partners and BTN. Adding Washington and Oregon would help with the content in football, but the way the media deal is written, they may need more programs to have the Friday primetime late night Saturday games. Those schools need to have away games in conference and USC/UCLA are paid for the Fox/NBC/CBS deals. They don't want to give up that inventory. Having 4 school with the ability to play those games makes scheduling much easier.
Honestly, I can see 4 more schools out West being part of the Big10. Washington, Oregon, Stanford, ASU, Arizona, Utah, and maybe Cal are all candidates (I really think Cal is at the bottom of the list and ASU is higher than you all think). Washington is a lock. The others are all in the mix.
I agree with this as well, but will need some more basketball oriented programs. The only true basketball schools in the Big10 right now are Indiana, Purdue and UCLA. MSU is pretty close, but will need to see what they become when Izzo retires. Wisconsin, Iowa, OSU and Michigan are the next tier down (either boring basketball or not consistent play). They need name programs that will create must see games. Those teams seem to be in The ACC and maybe one in The Big East that seems to fit the bill.
I don't think there is an end game here. Conferences will court as many teams as makes sense for them to make money and provide great marketing for their universities. anywhere from 16-32 is possible, but I think the sweet spot will be 20-24.