yup, i don't know how they do it for the newer models, but older ecotank models stop printing after 18,000 pages and show a warning about the purge tank being full.
you can clean the purge tank yourself and reset the counter with a key. there are plenty of tutorials on youtube.
afaik, epson doesn't even intend for the tank to be cleaned. at least not by the customer, otherwise it would be a dismissable message. the keys are probably meant to be used by epson themselves but are being leaked by someone.