Government mandates. Gotta meet stringent economy and emission standards. Chi ching. SUVs were practically invented by CAFE laws that carved out exemptions for them. Latest and greatest direct injection and variable valve timing, etc. don’t get you to the new CAFE targets. Stop-start gets a little further but gotta make the starter and oiling systems more robust. Still can’t get there though so now we have to add on many thousands of dollars worth of electric motors and batteries to supplement or replace the engine.
Then there are safety systems. Seat belts, airbags, ABS, traction control and stability control are all standard now. Now backup cameras are mandatory with giant dash screens in every car. New vehicles getting a whole suite of sensors and cameras to automatically brake when you follow too close, or buzz when you drift out of lane and enhance your vision at night but are building up to self driving capabilities. All that tech costs money.
Cars are engineered to last longer too. When I was a kid getting 100,000 miles was an achievement. Now we take it for granted that cars should never have a problem before then. I have a truck at 220k miles I expect to keep for years to come. My vehicles range from 11 to 27 years old and all run strong and reliable. That kind of quality engineering doesn’t come cheap (but it is worth every penny)
Two vehicles took me through 25 years on active duty - a Bronco II and a Bronco. Made more on ‘do it yourself’ moves than the first one cost. Sold the Bronco after 20 years when it hit 200k miles.