Actually streetcars are kind of a bargain because they use mostly existing infrastructure. But that’s the downside too, because they can easily get stuck in traffic. The LA Red Car system died in the end because without its own right-of-way, it was worse than cars, less convenient than buses.
Then give them their own right-of-way. Amsterdam trams go through the streets, but you're not supposed to block them. They often have their own lane (though frequently still shared with buses and taxis), and when they don't, it's because the street is too narrow, but that's usually only for a limited section of the street.
You still need tracks and power lines. If the only benefit of streetcars over buses is right-of-way, why not just give buses right of way.
After some deliberation, my muncipality recently decided against a streetcar-system and for a bus-based system with electric buses, right-of-way everywhere and dedicated bus-lanes where possible (nearly everywhere).
Actually streetcars are kind of a bargain because they use mostly existing infrastructure. But that’s the downside too, because they can easily get stuck in traffic. The LA Red Car system died in the end because without its own right-of-way, it was worse than cars, less convenient than buses.