The answer might surprise you (a bit).
I’ve found an interesting article about HP and its view on recycling and refilling toner cartridges for printers.
On a tour round one of HP’s facilities, the article’s author has an interesting exchange with two officials that and, given they’re representatives of a multinational, appears to be quite frank.
It makes sense that ink manufacturers would want customers to only buy new, official, products, not third-party or refilled cartridges. But it seems like that the stumbling block for HP (and maybe other printer makers) is one of quality and customer experience, rather than principle.