There was an OECD study on tax-assisted savings done in 2003-04. What that showed is that if you want to encourage savings by the lower income earners and middle-income earners you should have subsidies or grants similar to the RESP. If that's the target group that you're trying to bring in to save, as opposed to the higher-income earners, then you should look at grants like the RESP.
On May 26th, 2015. See this statement in context.