The government of Canada gave money to anyone who (1) was over the age of 15, (2) made more than $5000 in the year prior to the pandemic and (3) lost at least 50% of their wages.
CERB was $2000/4 weeks * 6 periods, CRB was $900/2 weeks for up to 54 weeks
So do the math ... you're a 18 year old student that made $5000 the year before the pandemic. The government potentially has paid you upwards of $30,000 to stay home over the past year and a half. You could go back to a $15/hours job (that's Ontario's minimum wage), but you have more money in the bank than you ever thought you would at this point.
It's not the older, "full time" worker staying home. It's that none of the students feel the need to work anymore.
And it's not just restaurants. I went to a very large, major chain, grocery store last night at 7pm. Half of the shelves were empty and they had ONE self checkout open (with a line of customers). No staff there either ...