I volunteer as a Cub Leader, and I do it because I love it.
It is time consuming, and takes some training, but there are smaller roles, for instance one of my assistant leaders does every other week as he works shifts.
We frequently have weeks off, if we are away on holiday etc.
Since covid, there has definitely been a reduction in volunteers, as some leaders, I think, realised just how much time and effort they'd been putting into running a group, once they were no longer doing it over lockdown.
Also, I think the pressure on parents these days is far more, often both parents working full time, so they are less likely to volunteer, and older people are working longer and retiring later than they used to.
Also, there's a definite trend towards people wanting more for less effort. Parents now want their kids to do everything - football, swimming, music lessons, cubs/brownies etc, which means they spend their entire week running around, getting their kids to clubs, and then feel they have less time to give.