You are right, the general consensus is that so if we heatsink it we increase its rating. I just think the net worth of this is not necesarily predictable. Let's say we put the resistor inside a hotend and do a very good job at insulating that hotend, that insulation again changes things the other way because ofc insulation stands in the way of eventual dissipation. So if we heatsink it we increase its rating, and we insulate hotend which decreases that rating. I dunno how to account for everything, so i think overall result probably vary for each particular case.
The cemented resistors imo have poor structure, i mean their internal cement is just that, not the expensive thermal conductive stuff, and there is a bigger distance between heater wire to outside shell, through cement, then through ceramic case, so that makes a long and poor thermal junction from the start. Also a failure mode i think very probable is their leads failing and breaking, and this one is not really being about the resistor itself just its leads.
The cemented resistors imo have poor structure, i mean their internal cement is just that, not the expensive thermal conductive stuff, and there is a bigger distance between heater wire to outside shell, through cement, then through ceramic case, so that makes a long and poor thermal junction from the start. Also a failure mode i think very probable is their leads failing and breaking, and this one is not really being about the resistor itself just its leads.