That's because the LCBO has a monopoly on wine sales in Ontario and it's very difficult for Ontario wineries to get their good wines into the LCBO. It's a combination of shelf fees, minimum volume requirements, and an idiosyncratic evaluation system where their participation costs are not covered.
Spend some time at wineries on the Niagara escarpment and you'll find some great wines, especially whites that benefit from the limestone heavy soils. Even the large producers that have a poor public reputation for quality (Trius, Iniskillin, etc.) have much better wines available on site that never make it to the LCBO. For the most part (some exceptions), the people who run these wineries are wine enthusiasts who genuinely care about quality. Prices for that quality are higher than other wine regions with more favorable climates, higher production, and lower labour costs though, that is true.
