The fear is justified, but it doesn't really happen that way.
When the Canada and Quebec pension plans were launched in 1966, and when tax rates increased from 3.6% to 9.9% between 1987 and 1989, it was difficult for small businesses, but they were able to absorb these additional costs.
I don't see why a minimal increase like the one anticipated, which would cost 3% or 4% of the salary, so 2% for the employer, could be a major obstacle. The increase could be absorbed by not giving salary increases for three or four years. In fact, ultimately, the employees are the ones who still absorb the costs.
So it's a problem, but I don't see it as a major obstacle.