The research might be paid for by tax-payers money but journals aren't, they cost significant amounts of money to run (it typically takes a decade before a jour

The research might be paid for by tax-payers money but journals aren't, they cost significant amounts of money to run (it typically takes a decade before a journal builds enough of a reputation to break even). You could argue publicly funded researchers shouldn't submit to non-open journals, but that's not an argument for depriving publishers renumeration for the work they've done. The profit margin for both closed and open-access journals is typically around 20% (for some of the top-tier journals it goes upto 30%) - except with open-access journals it really is the taxpayer who is paying for the publication as the author's institution typically picks up the cost (as opposed to non-open journal where the cost is distributed among customers of the journal).