Quite. Cut off the head and the Tories will do what they did with Johnson, claiming they’re a new and different party now, rather than one that's been in power and doing increasingly shitty things since 2010.
Labour and the Lib Dems in particular (along, to a lesser degree with the Greens and Plaid) really need to get their shit together, figure out how to cooperate, and educate voters on how one “hold your nose” election could eradicate the Tories and build a system that makes it very difficult for them to ever get into power alone again.