Exactly. The high cost, inflexibility, and maintenance requirements of overhead wires all make them unattractive for new installations.
Battery electric buses, on the other hand, can operate anywhere that diesel buses can, and a fault with one bus or one section of wire will not break the whole route.
Many cities also consider overhead wires to be visually unattractive. Birmingham's new tram network is being built to use overhead wires on suburban tracks, but switch to battery power in the city centre to avoid having to install overhead wires there.
Battery electric buses, on the other hand, can operate anywhere that diesel buses can, and a fault with one bus or one section of wire will not break the whole route.
Many cities also consider overhead wires to be visually unattractive. Birmingham's new tram network is being built to use overhead wires on suburban tracks, but switch to battery power in the city centre to avoid having to install overhead wires there.