I'm not sure if the streetcar abandonment policy was as absolute as: abandon all streetcars. Rather it was the gradual removal of many mixed street-running routes, and the upgrading of other routes to more modern Light Rail. Most (or all) of the Queen Subway proposals I've seen - some of which occurred during this "policy" - were to use streetcars/light rail. Run underground downtown, and along the surface outside the core - possibly on an ROW of sorts.
So I think had the policy continued, we still would've ended up with streetcars on some routes, and some significantly enhanced/newer streetcar routes. Not an outright or complete abandonment of the streetcar/light rail vehicle. Though I'm not 100% on this.