The flippers generally increase the housing market values temporarily. There is no way you can sell a flipped home for the purchase price you paid since any renovations are so crap and generally don't touch the mechanicals.
It's basically the equivalent of putting a new paint job on a rusted out 1995 Chevy with 300,000 miles on the odometer and yes there are some idiots that will buy those houses and then get in over their head between debts they incur repairing their homes and the higher mortgage they got into and higher property taxes than their neighborhood is actually valued at. The problem is that housing market values and local wages are closely tied together, so these people will generally not make enough to make payments + maintenance on the 'nice house' that is falling apart inside.
hat drove the housing bubble was primarily government forcing and backing sub-prime mortgagees. People that couldn't afford a house but through various incentives were promoted into buying a house they actually couldn't afford. Besides the government providing banks the difference between the "market interest rate" and the "woke interest rate", there were programs in NY and CA that effectively paid your mortgage if you were of certain race and income, but once those incentives disappeared, which is inevitably what happens, the banks had to adjust for the real market value of the loans leaving those people on the hook for insane mortgage payments on an adjustable mortgage which the banks used to recoup any losses they had made during the "woke years".
Whenever the government gives money, the market value will adjust to absorb these incentives. It's why college/university tuition costs are so high, because the government basically gives sub-prime loans to the students who don't have to pay for about a decade or so which sounds good, until the first payment is due and you've accumulated 10 years worth of interest. So colleges adjust their prices to adjust their value for this free money.
It's the same problem as the minimum wage, you can increase it but that compresses all other wages and the market has to adjust accordingly. So the entire market moves up $10 which is reflected in the cost of products at the store, so in the end, the value of the extra money is absorbed again in the market as everything becomes more expensive. You can give people $100/h in minimum wages, it will just make whatever is currently valued at $15 cost $100 in the future and more likely $115 to recoup the losses from the inevitable recession that follows a minimum wage increase.
Everything seems to go through this cycle between "woke equity" and "real equality". Businesses can't operate at a loss indefinitely, there is no such thing as a business owner swimming in cash like Scrooge McDuck, money that doesn't move has no value. But the woke seem to think that we need to take these cash reserves from anyone that does any better and redistribute them, which inevitably leads to a backlash against higher taxes and regulation during which businesses have to recoup their losses.