The population of Markham has grown ~50% in 15 years. (223K in Jan 2002, 353K in 2018)
The city's planning documents from ~15 years ago projected a 2030 population of around 342K. We're 13 years ahead of that forecast.
Height restrictions are being loosened on new buildings in Markham Centre, meaning even more intensification in the area.
Even if the growth slows to 33% in the next 15 years, the 2030 population will be around 450K.
Add the new York/Seneca Campus, new commercial buildings and retail ...
The transit is needed for the future.