1. Intel doesn't have to catch up. Intel's 14nm is more than enough for a lot of fabless. Not every chip needs cutting edge node
2. split up Intel foundry into a pure play allowed Intel to build up an ecosystem like TSMC.
3. Intel's 10nm is much denser than TSMC's 7nm. Intel is not too far behind. they just needs to solve the yield problem. split up Intel's design and foundry allowed each group to be more agile and not handcuffed to each other.
in fact Intel Design should licensed out x86 like ARM. why not take best biz model from the current leaders? Intel Design take ARM business model and Intel foundry take TSMC business model.