Some do it better than others. 351C has the thermostat setup so the bypass closes as the thermostat opens. Many other engines do this as well. I remember a friend's 80s BMW that had a remote thermostat with 3 large hoses going to it. It was a bypass style as well.
Motorcycles have done it as well. Back when I was in the KLR world a taunted upgrade was the thermo-bob. The seller had data showing a more stable coolant temp with his remote bypass thermostat over that of the factory non-bypass thermostat. Oooohhh bling, has claims and some data provided by the seller to back it, must be better. I pointed out that countless bikes (including my own) were very high mileage and no issues with the stock thermostat and still running the factory top end.
As for how Ford did it. If you look at a factory thermostat housing (not counting aftermarket at this) the bypass hole is actually fairly small. The 5/8" hose is way bigger. But what they had buckets of hose clamps for going down the line. When the thermostat is open, very little coolant is going through that bypass.
Another thing is heaters. Not the Bronco, it has a shut off valve. But the millions of vehicles that don't have a coolant shut off valve that flow coolant through the heater core 100% of the time. That flows way more water around the thermostat than that tiny bypass hole.
Many decades ago I thought I would try and out engineer Ford. Living in AZ I wasn't really worried about warm up time, and through a little extra cooling would be trick. I took a stock thermostat housing and tapped a pipe plug into the outlet. I think I got by with a 1/8NPT plug. Then I drilled a crossover into the housing bypassing the thermostat. Wasn't a big hole, just wanted to emulate the bleed of the bypass but go through the radiator. It did slow the warm up time a lot, but did nothing to the overall coolant temps. In other words, I made it worse at warm up and improved nothing in the process.
