I happened to be passing through Texas the very day the limit on I-10 and I-20 went up to 80 mph. On I-10 westbound this was as you entered the next county west of San Antonio, and the first Speed limit 80 sign I saw I thought, "Wow, common sense is breaking out out West!!"
I didn't even know it was the first day until I saw a local newspaper at one of our gas stops. (You have to gas up several times to cross Texas!!! I-10 at the Louisiana line is mile marker 880, and we were headed to the exit at mile marker 13 in El Paso.) The newspaper emphasized the zero-tolerance policy on the higher limit, no cushion. Basically, it had no effect on actual traffic speeds, it just made what people were already doing, legal. The speed limit ought to be at an 85th-percentile speed, i.e. the speed above 85 percent of the traffic.
As for Ontario, never been there. I hear it gets cold in the winter so I'm probably not interested. But if most folks are already doing 80 mph, then that ought to be a reasonable actual limit based on teh 85th-percentile guideline.