Yup. The average age of a car on American roads in 1979 was 5.7 years, and that was up from 5.1 years in 1969. The 2013 figure was 11.4 years, just about double the 1979 figure. It hit 11.7 years in 2017, and the 2021 figure is 12.1 years. That's the average age. That means cars last longer now.
Most gas stations used to have service bays and a tow truck. Now, they mostly don't; instead they have convenience stores. That's because cars and all their many parts fail a whole lot less than they used to, so service bays and tow trucks just don't pay their way any more. Not like they did back when most cars had 5-digit odometers.
All of this is true. As they say, it's a lot harder to design and engineer a water pump for a Dodge than for a Rolls Royce, because the Dodge water pump has to do the same job over the same lifespan for a whole hell of a lot less money.
Wikipedia says the SC400 was made between model years 1992 and 2000, and average annual mileage on a car in the US is about 13,000. So if the failed part in question was original to the car, it was between 23 and 31 years old. That's a couple-few decades and a couple-few hundred thousand miles worth of thermal cycling. The repair part costs between $5 and $15 on RockAuto, or $36 from Toyota for an OE part. Just how much longer is it reasonable to expect a thermostat housing to last?