You're talking about new inventions, which misses the point. Any technology will experience a cost decrease in its beginning but then it levels out. I'm sure before the Ford Model-T came out cars were considered a luxury item for the wealthy, but people were also doing fine without cars. Yet the Chevy Malibu of 1970 when adjusted for inflation was cheaper than a Chevy Malibu of today. There will be no point in time where a new vehicle costs $2000, it just won't happen.
Below a certain price point, people want more features instead of a cheaper product. The Chevy Malibu is not the same product it was in the 70s - it's barely comparable. In terms of safety, reliability, performance, and fuel economy, the modern version (which is pretty bad across the board by today's standards) blows away the 70s version. There's both called the same name, but they aren't equivalent.
There is no connection to the price point of a product and the cost to make it, what matters only is demand.
And, you know, supply. That's why the price levels off at some point: stuff becomes fully commoditized, margins fall to where there's little point in new manufacturers getting involved. But even then, over decades, things change. Washing machines, TVs, and refrigerators are much better product now feature-wise that 60 years ago, even if they don't last as long. (And I don't know what fancy rich enclave you grew up in, but where I grew up most households were single-mother-income, and still TV and fridge were taken for granted).