This can actually be pretty bad for travel time as well, because then the bus has to wait for a break in traffic to get back on the road. Now in the US many places build bus stops out to the road lanes so that they don't have to waste time pulling in and out of traffic.
This seems less a problem of trams running in the middle of the road and more of a problem of localities that don't build suitable waiting areas next to the tram tracks. Example: https://nacto.org/wp-content/themes/sink_nacto/views/design-...
The bus behind could have driven around, but the next tram was stuck until the blockage was cleared
Now, if the busses had dedicated lanes that they could use, they may run as well as trams, with the flexibilty of changing route for exceptions like crashes, or road works
The trams in melbourne suburbs usually drive down the middle of the road, and stop in the middle of the road, meaning people exit in the middle of the road and have to walk across it to the footpath, halting the traffic. Conversely buses pull over to the side of the road, usually into a lane that is used for parking, or at the most stopping only the one lane of traffic.