Of course it is possible for council to change it's mind again and again continuously, they could also cancel everything, and so could the provincial government. My point was that just because transit taxes happen, it doesn't automatically follow that the plan for a given route will switch technologies.
The implicit assumption you make is that subways are better, we would all like to build subways over LRT if only we had the money.
You have to recognize that for some people, LRT is actually their preferred choice for a given route, it's not something they are settling for due to lack of money, believe it or not. Just because money becomes available doesn't mean an LRT plan automatically becomes a subway. Sure, it's possible, but it's not automatic, there are actually reasons to stay with LRT for some routes, even if more money becomes available. It is true that LRT is generally cheaper, but that money can be spent on the tons of other projects in the Big Move, of which there is no end to the supply.
For example, there was money to build a Sheppard subway, but many Torontonians believe this was the wrong choice. There is no universal assumption that subways are better than LRTs for all routes, and that if we could only afford it we would want subways everywhere. For some routes, some people believe LRT is more appropriate.