Why aren't there more flight routes between South East Asia and North America?

Air Canada launches North America's only nonstop flight to Bangkok
https://edition.cnn.com/travel/article/air-canada-non-stop-bangkok-vancouver-flights-cmd/index.html

I had thought that there would be regular flights to North America from South East Asian cities like Ho Chi Minh, Kuala Lumpur, Bangkok, Manila, Singapore, and Jakarta. But, there are no flights between these cities, except for the flight between North America and Singapore and this flight between North America and Bangkok.

I wish there would be those flight routes in the future.