First, cell phones ate EVERYTHING. So, the only volume is in cell phones. Cell phones only need a few different types of chips but they need them in massive quantities.
Second, the cost of creating a chip is too high. The "maker" culture relies on the fact that creating a PCB is cheap. Between the cost for EDA VLSI tools and the NRE for creating a mask set, you blow $100K before you even get started making a chip. I suspect that we probably have the ability to digitally image 1.0um or larger features so we don't have to cut a mask set, but it's a chicken/egg problem. Since nobody wants 1.0um+ processes anymore, nobody will develop the technology for them, so nobody will design for them, so nobody will want 1.0um+ processes.
Third, modern fab capacity is ridiculous. A single 300mm wafer can produce 70,000 1mm^2 chips or 700 1cm^2 (a big chip nowadays). How many customers can consume those kinds of volumes?