Well, first you have to ask why rimfire firearms are so inexpensive now. A few reasons: low pressure means high strength forgings and high-strength barrels and high-precision high-strength components are unnecessary, low pressure and low graving forces of lead bullets mean threading barrels into receivers is unnecessary, soft lead bullets or thin copper jackets make more expensive barrel steels unnecessary, short action length makes large forgings for actions unnecessary, low to medium accuracy expectations mean close tolerance barrels and rigid barreled action assemblies are unnecessary, low cost stocks and short-range scopes add to the low sticker price. Shall I keep going? All of the things that add cost to manufacturing can be minimized, and the cheaper items are all that is needed, so the cost is low. None of those will change, so the cost will remain low compared to centerfire rifles. Now, will centerfire rifles become expensive? You bet, but no more than the market will allow, or people will not buy them. We live in a free market economy, after all. Even in the former Soviet Union, firearms were relatively expensive but the market demanded them so they were available.
Never try to educate someone who resists knowledge at all costs.
But what do I know?