Because 2 MB blocks don't solve anything. All it does is kick the can a little bit down the road.
I guess we all know that. BIP 101 was suggesting 8 MB blocks last summer! This didn't go through so the bar has been lowered.
I don't understand why most miners don't want to see big. We need to find a solution which would allow one hundred times more transactions. Let's imagine 1% of humanity doing one transaction each day. Does that sound crazy?
That would be 71 millions transactions each day but the network is already stressed at 200,000 daily transactions. Unless there are major changes, I can't see a bright future for
BTC. And change must come as soon as possible. Every single day without a change makes investors less confident.