The materials in a 60hz transformer I think are the main BOM cost for linears? Relatively, transformers are say 2x cheaper than in 1970 (steel and copper are relatively MORE expensive than they used to be but the manufacturing improved) - but chips are more like 100x or 1000x cheaper. The high frequencies of switchers let you shrink the transformer (less materials) so its a big win.

Also the waste heat of linears constrains your design in terms of weight, power density, how big you need to make the enclosure, etc.

For reference I looked at what I'd need to buy on AliExpress to power my laptop off the cheapest linear PSU I could find (say 20v 5A), something like: https://www.aliexpress.com/item/1005003397909174.html - it weighs 4kg vs 300g for the charger I have. Apparently there ARE audio people who put their NAS on a linear PSU (I did not realise that was a thing!) but I'm going to try to forget I saw that.