It's not about mandated wage increases, it's about people like you and me running or voting for representatives that will pass bills that over all decrease the gap between cost of living and income. This can be achieved through many avenues, wether through taxation, regulation, or subsidies.

Taxing the rich will increase tax revenue that can be used to subside material costs of a house (there for decreasing building costs). Charging higher taxes for non primary residents and or corporate purchases will reduce the cost of homes, allowing those who need a roof over their head opportunity to buy, rather than tho who just wanna pad their portfolio.

Regulating the pay gape between the highest and lowest payed employees (including stock options) will increase overall wages for all (except the few that already make more than their worth), making a 300k house affordable.