Not exactly. Very early cars wouldn't last 100k (and the odometers reflected this) simply because the technology and know-how wasn't there.

As time went on, car building was refined to the point where they could last 1 Million miles.

Then manufacturers realized that most people didn't keep their cars very long, and wanted them to be cheaper to buy. So even though we have the ability to make cars last a long time, they are engineered to be produced as cheaply as possible , while being just reliable and durable enough to keep most people happy. Now they last 100k to 200k miles. So we've come full circle.

Also, modern cars are crammed with so much technology (electronics) it can make your head spin;  even if the powertrain and drivetrain last, you may be limited by the electronics.  Another thing standing in the way is planned obsolescence.

I would say hitting 1 million miles is a lot harder nowadays than it used to be.  I would even say we are past the pinnacle of Toyota reliability as they have steadily gone downhill;  I don’t think their newer cars will last as long as some of their older ones.  They still are better than their competition here in North America in terms of longevity, but they have still slid backwards.