Just going off the top of my head.
2x6 exterior walls instead of 2x4.
Insulation for those walls.
Attics I believe now require r60.
HRV systems.
Copper wire is at retarded prices.
AFCI and GFCI pretty much everywhere now.
Hardwired smoke detectors with flashing lights.
Recirculating pump and line for runs longer than a certain distance (can't remember the number).
Drain water heat recovery pipes.
Anti-scalding mixing valves.
Plumbing materials have gotten cheaper and is way faster to install (pex vs copper).
Cost of labour has gone way up in the last 10 years or so for all trades.
Then there are the wants. Carpet is basically non-existant anymore. Tile and wood are far more expensive. Curbless showers instead of fibreglass pans. Kitchens loaded with granite even though most people couldn't make a sandwich to save their life.
All the crap adds up. And this is just off the top of my head. There's more for sure.
I'm a supporter of passive systems so the 2X6 walls and insulation are OK.
Building materials are subject to inflation like everything else so copper pipe and wire are a necessary evil. A 4000 SF house has ~ twice the evil of a 2000 footer.
Heat recovery systems, mixer valves, sprinkler systems, active solar systems etc all require maintenance which is money you can't put towards the mortgage payment. If they are complex it means $150 to $200 an hour for service.
Granite looks like crap if it doesn't get a spa day once or twice a year so, in comes the guy with a buffer. $150 taps don't look right so to balance the posh factor the taps are 5X the price.
To maintain the posh balance throughout the house all trim in all the rooms have to be posh. If you don't do it, the plain rooms stand out like a half iced cake.
The tax man notices how expensive your house looks and smiles.
What does a couple need in a house?
My cousins had a place in Rochester NY when Kodak was solid. No kids but they entertained a lot in their story and a half, three bedroom detached.
It had a 30 ampere 120 volt service, two fuses. One circuit did lights and the other did receptacles. The stove and clothes drier were gas and the furnace gas with no fan. It relied on convection. Other than going through a lot of fuses when someone tried making toast and tea at the same time it worked fine. You had to be patient.
You also had to be aware of what other people were doing in the house so no toast or tea if someone is drying their hair. You also had to think about usage.
Labour rates are high so your DIY efforts, if done right, pay you higher rates. You get your hands dirty but the tens of thousands you save buys a lot of soap.
Inflation is dependent on inflated egos and too many people have distorted expectations expectations.