Clogged cartridges aren't the major issue. Clogged print heads means your printer is ruined and you can dispose of it.
Except for HP printers where the print head is in the cartridge itself.
I've had great successes undoing clogged head on Epson printers with just few drops of isopropyl alcohol on ink drawing port. Weirdly the clogs don't even reproduce thereafter, so it might be silently doing something horrible, but worked for me.
Where did you hear that? You can buy replacement print heads for all cartridge-less printers I've ever worked with, including my ET-8550.
The difference is that they're purchased separately from the ink, so as long as the original one works you can continue to use it no matter how much ink you go through.