How can we fix gentrification and have more affordable housing?

Gentrification is inevitable while housing is unaffordable in many areas - people in London for example are moving to areas like Hackney (previously not considered, now rapidly rising prices) because they can't afford anywhere else.

organised vandalism and criminal activity in up and coming real-estate areas

Live outside the city, in a less populated state.

We own our home and rent out half of it (three bedrooms, living room, bathroom, and kitchen) for $500/month. Not at all an uncommon price for a rental in this area.

I drive 20 miles to work.

Meanwhile a friend who lives in the city pays $1,200/month for her rental home.

One solution is to have more equitable incomes - that is, to give working people higher salaries.

build more homes.

"We"? Do you have a mouse in your pocket? Gentrification is more or less a naturally occurring piece of the lifecycle of a neighborhood.

A lot of people are happy with gentrification. They benefit from the rising house prices.  Why bwould they want it "fixed"?