Except that's not how it works in Europe. You go to cities like Berlin, Tokyo, Madrid, and even Sydney , and they have extensive highway networks, even moreso than what we have here in Toronto. The reason why Transit has such a high marketshare then is because transit in these cities IS COMPETITIVE WITH THE CAR. I can take the U-Bahn in Berlin, and comfortably get from one side of the city to the next with barely any issues. Meanwhile in Toronto we're building subpar Light Rail lines that stop at every red light, and that ultimately don't show any advantage over the car. People don't take the car because they're stubborn, people take the car because most of the time its the best and most convenient option.
I believe public transit is popular in Europe due to a combination of factors. Good price / high subsidy level ceratinly plays a role. And, many old capitals have extensive subway networks, built at the times when construction was cheaper. Plus, the built form: if driving the car is easy, but parking the car at both your destination and at you home in the historical part of the city is a chore, then you are less likely to drive.
European cities often have good highway networks; attacking the cars with artificial traffic jams is not the strategy they use. They do restrict or close certain areas for cars, that applies more to the final destinations than to roads leading there.
Though, I would not call the Eglinton LRT design "subpar". That on-street eastern section will have minimal effect on the line's performance, because it is short. That 9 km stretch can be travelled in 24 min at 23 kph (surface LRT speed), or in 17 min at 32 kph (subway speed with a wide stop spacing). So, we are looking at a ~ 7 min diff in the travel time. Maybe some people who can take either Line 2 or the LRT, will opt for Line 2 because of that extra travel time on LRT. So what, the eastern sections of both Line 2 and the LRT will not be close to full capacity for a long time, if the Ontario Line is built.
Yes, it will be slightly odd to have the lightly used western section all grade-separated, while in the east, the grade separation only reaching Laird and not even Don Mills. And, knowing before hand that the west will end up being grade-separated, it would make most sense to do the same in the east.
But I prefer to look at the situation this way. Going from the mixed-traffic buses that always get stuck, to the hybrid LRT design (partly tunnel and partly street median), delivers ~ 80% of benefits. Going from the hybrid LRT to full grade separation, would deliver the remaining 20% of benefits. So, the proverbial glass is certainly more than half full.