Competition is not opt-in, especially when it's about scarce but required resources such as housing. When the majority of households in the market became dual

Competition is not opt-in, especially when it's about scarce but required resources such as housing. When the majority of households in the market became dual income, every single income family inevitably had to compete with them for housing as the prices for that have gone up to what the dual income families can afford to pay - and with that being a so large portion of most people's expenses, simply accepting 1950s (for example) living standards won't be sufficient to for a single income family to afford renting or buying a home in that city.