Your home is worth so much because the influx of illegals (and legal immigrants, and those who overstay their visas) and the number of native-born citizens has risen incredibly fast in the last 20 or 30 years. The US population will reach 400 million by the end of the century, even without any immigration. And your home will be worth a lot more, and no one will be able to buy it except a corporation or a millionaire. 

Then it will be rented out, maybe, to an honest hard-working American couple who will work two jobs each just to make the rent. This is the future of the USA.