Epson heads are just too small for most applications. Look at the size of the heads in the Kornit, or many of the wide format digital printers. They are double or triple the size of epson heads. The ports are larger and they are built for industrial applications. Epson print heads work fine...for paper and film it turns out, but both of those are very similar media.
Epson heads tend to clog very quickly too and screen rooms are a pretty clean environment, but they aren't perfect.
