Here's my take on this - it's evolving consumer taste and expectations coupled with lower manufacturing costs.
It's just the same as the automotive industry. There was once a point in time when fuel-injection was considered a luxury. Now you can't buy a car without it. Satellite radio used to be a selling point. Now most new cars have it.
My point is that some features and qualities that used to be high-end cascade down to lower-end products as a result of competition for the almighty consumer dollar.
Evolving tastes and expectations is a result, not so much a driver...
The cost has to come down to a point were the average comsumer is willing to pay for it.
To further your analogy, we have in our cars air conditioning and lock remotes that are now a given, most people would just expect this to be standard equipment, but once were a luxury, and costly add-on, however, FLIR technology has been around for about as long as the remote loor lock, and is currently available today, but at $2000 to $4000, the price is still just above what the average guy is willing to pay.
When the price drops to about half of what it is now, it will show up as an option on
most all higher-end car models*, and when/if it drops to under $400, it will start to be standard on luxury models.....
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*It is an option from some luxury makers now