A few observations. I used to work for a company based in Oakville, ON, and after flying through Pearson initially, I ended up driving to meetings from my home just north of New York City. With all of the wait time, driving was just as fast (7 hours). And since there is no baggage restriction when you drive, I always had my camera equipment with me!
Secondly, due to the outrageous travel taxes Canada charges US flights, you will find driving to Buffalo and flying out of there to be a lot cheaper.
Finally, I don't think the problem is specifically with the GTAA, but with the national government. Once coming back to the US on the Lewiston-Queenston Bridge, we were stopped by Canadian customs for a while. Apparently, according to the news, their union was in negotiations with the government, and they decided to halt everyone going to the US as a labor action! So, perhaps the jam-up at Pearson may be do to a similar labor situation, not the authorities.
Now, the Canadian government has eastern New Yorkers upset. They want us to build a large customs station at the border on the New York-to-Montréal Amtrak rail line and require all passengers and their luggage to disembark for a 100% search. Processed passengers can then reembark, and the train will proceed to Montréal. This is probably the only rail line fast enough between the countries for business people to consider, and the Canadian government wants to destroy that connection. Rail travel to and from New York State and Toronto is not very practical, because there is an hours' long stop for tourists at Niagara Falls.