With electric buses, at least, you can put the chargers at end point stations, which is a cost but one bussing agencies can handle. Also, they cost much less than the overhead wires electric trolley buses currently use.
One idea I've read is to use those overhead wires for BEV busses, but only on certain segments. Most bus lines loop through a central area, so could charge along a section of a few blocks that feature the overhead wires.
Wire attachment is a big problem even for bus line me that are fully overhead. Before the buses had batteries, a detachment often required shutting down the road and bringing out a big truck to reattach the bus.
Seattle used to run dual gas/electric (not really hybrids since no battery) in the downtown tunnel by having them attach going in and Unattach going out. Great when it worked, but it often didn’t, so they just use cleaner emission buses now instead.