I imagine that if internet forums existed 100 years ago, the exact same analagous debate, with analgous arguments one each side, would have occured on the topic “When will automobiles become mainstream”.
It only took 2 years for New York city to be 99.999% horse driven to 99.9999% ICE. That was in 1912. People were tired walking though horse poop that could be 3 feet thick on some days. And any idea how much horse urine there was? 60, 000 gallons. If I'm not mistaken in 1920 New York on a daily bases had to deal with 2,500,000 pounds of horse poop. Average life expentancey of a working horse was three years. They would drop dead on the street and left to rot for days. Similar story every other city in the world.
Simiar story in London with the "Great Horse Manure Crisis of 1894".
https://www.historic-uk.com/HistoryUK/HistoryofBritain/Great-Horse-Manure-Crisis-of-1894/
Haven't we already seen some cities ban smelly diesel trucks during certain hours so shoppers would not be exposed to diesel fumes?
Well in 1920, according to your numbers, there weren't very many horses in NYC. But your point about there being a tipping point with a high Q rings true.
But there was a lot of resistance to transitioning from horse to automobile throughout the US. Keeping a horse was labor intensive, it could only go so far before needing a rest, you had to feed it even if you didn't ride it and the manure needed to be dealt with on a regular basis. But even with all the benefits of auto ownership, people resisted. So, I don't find it surprising that people resist EVs.
Perhaps the bigger question is will people actually own cars in 50 years? Or will we have massive fleets of self driving Uber cars. All EVs, of course.
If you lived on a farm, "fuel" for your horse was, for much of the year, free.
Most people didn't travel really long distances, & when they did, scheduled their trip so the horse & owner could "recharge" overnight.
At least in Australia, the Great Economic Depression put a serious kink in the take up of cars as horse replacements.
This was followed at breakneck speed by WW2, when fuel was rationed.
Some cars had charcoal burning "gas producers" fitted, others were used very sparingly, with many garaged "for the duration", with their owners reverting to public transport, bicycles, &, yes, horses.
Hell, we had a horse & cart when I was a kid in the early 1950s, being one family of several in our small town who did this.