Brisbane's "narrow" streets (actually they're not that narrow) have nothing to do with the closure of the tram system.
It's interesting to look back at old Brisbane City Council annual reports - unlike many other tram systems, Brisbane's trams ran at a profit until the early 1960s - and you can trace their patronage decline to when the City Council started building off-street, multi level car parks - Gregory Terrace car park was the first one, opened in the early 1960s. Now Brisbane has more city car parks than any other city in Australia. Before then you didn't drive into town, because there wasn't anywhere to park. You caught a tram or a train. And with the exception of Chermside, there were no big shopping malls surrounded with hectares of car parks.
At least Chermside shopping centre was at the end of the tram line.
Check out the Town Plan too - also first introduced in 1964 - it has a whole chapters on car park requirements for developers and nothing on public transport requirements for developers.
Now people forget what Brisbane was like and say "the trams can't be introduced". I've even heard people say "but the overhead wires are so ugly" - Like a traffic jam is a thing of beauty ???
Trams were quicker than buses - with 4 entrances they loaded MUCH faster than buses, so they don't have to stop as long at stops. Also they have better acceleration and braking than buses. Even more so with new trams (although Brisbane's trams were pretty sprightly).
It was a conscious decision by the BCC to go down the car, rather than the public transport path. In the 1950s and 1960s we had the highest usage of public transport in Australia and now we have the worst. Even Perth has caught up with us (thanks to their new train line).
'Simple' solution in Brisbane - close the public car parks (or tax them out of existence). Ohh, can't do that - there's not enough buses.