IMO a bear market is the best time to mine if you own the equipment outright and can afford to pay your electricity bill without selling for fiat. This is especially true if you paid retail or lower for your gear. Oddly enough it seems like values have appreciated compared to pricing pre-chinese tariff.
You are right but the reason why a bear market is a good time to start mining is low mining difficulty, if no miners are leaving the network it will make no sense, look at the situation right now, we are in bear market but not as dip as that of 2018 where people are switching of their rigs, mining difficulty is still very high still.