You are absolutely right that it’s dumb that it took so long for us to have discovered these receptors so late. Consider for a second though that this might be a symptom of a fundamental myopia in the way biological science itself has progressed? That perhaps we have been congratulating people for the wrong thing - discovering expected genes instead of finding new ways to do everything faster or finding things that are completely unexpected. As much as heat and pressure sound like fundamental senses (they are), they aren’t very high on the priority list of basically anyone trying to do biology with applications in mind. Heat receptors don’t cure cancer or cystic fibrosis. Or Covid.