There are 1.5 times as many people in the US competing for the same amount of land and buying houses using mortgages that are around 40% cheaper and many mortgages accept down payments that are 1/6th the size versus 1975, with underwriting that judges debt-to-income of 36% as “ideal” and some programs allowing 50% versus a limit of 25% in 1975, meaning the same amount of 1975 Americans plus the 50% extra Americans can all bid way, way more for that house you want, forcing you to pay up if you want it more than they do. In that time period, dual income households went from a minority to a majority, further heating up the competition.
Houses are also around 1.5 times the size with more bathrooms per bedroom in 2025 vs 1975, so “build less square footage and less fancy per square foot” isn’t at all “giving up so much that was standard 50 years ago”, but rather returning toward the standard of 50 years ago.
Sounds like you found a niche that market hasn't exploited then. Can I build a small house for fraction of the cost or most of my cost is going to be land?
Land cost depends on the location. You can find an acre of rural land for $1K. Or an 1/8th acre for $1M or more in a city.
For a cheap parcel of land in an unincorporated area with no building permit process, but with existing grid power, you can buy and build quite reasonably. (There are several YouTube channels covering builds like this.) In these areas, I wouldn’t overlook existing properties as well.