>>2051972They are being actively kept from getting close enough to the wire to touch them in wind. This added efford is part of why this setup is not common.
Another factor is that trams usually run rather low voltage (600 to 750 V is common, almost always DC too), so arch-gaps remain reasonable. This is mostly done so that if one of the wires comes down, which it will eventually, this is less of a problem than on a proper heavy rail-line.
