Even when people can get a subway, people still support LRT. See Forum's Scarb Subway poll that still has a majority of Toronto supporting the LRT, even though the poll was [likely] designed to lead people to support the subway.
First of all, I was talking about "active" support, when people demand their line being built and contact their elected officials to make it happen. A poll is a different situation, when people are asked to state their preferences, but are not required to take any further steps.
Secondly, the poll you mentioned is actually biased
against the subway option. People were asked whether they prefer a 7-stop LRT or a 3-stop subway; naturally, they decided that 7 is better than 3, without bringing the rest of context.
A fair question would mention all major pros and cons of the LRT and subway option.
The LRT option:
- Is much cheaper
- Has 7 stops versus 3
- Has an important stop at Centennial college
The subway option:
- Eliminates the transfer at Kennedy
- Integrates much better with the Sheppard East transit route
- Has an important stop at the hospital
- Two of the stops lost by not building LRT (Ellesmere and Midland) are amongst the least used on the system
- There is a possibility of adding the 4-th, well used subway stop at Eglinton and Brimley, though it requires extra funds
- Does not take space in the Uxbridge Sub rail corridor, which may be useful for the expanded GO Rex service