Not a bad hypothesis, but it's not right. FIFA's regulations for Men's World Cup matches includes approved artificial turf. It's in the regs for Russia 2018. For 10  group matches, don't be so sure that FIFA wouldn't accept turf fields to keep Canada in the bid. 

Second, the Canadian men's program is on an upswing and might not be so "humiliating" in 2026. It is every bit more likely that Canada will be ahead of where the US was in 1994 in terms of development. 

The one issue is stadium use, but the usual timing is mid-June to mid-July. It's potentially interrupting CFL pre-season and first few weeks. That can be worked around as it was for the Women's World Cup.