Flipping houses isn't necessarily a bad thing. It got out of control during the bubble, because people were basically buying property and riding the wave up. Eventually a bunch of people lost that game of hot potato.
If, however, the strategy is to buy a rundown house, fix it up and then re-sell it, that's slightly different. It's based on making improvements to the asset and not just hoping it magically appreciates. I used to watch a lot of HGTV and there were so many times I'd see a show where someone walks into a house and decides they don't like it beccause the color on the walls or the appliances. People are generally willing to pay a premium for houses that don't need any work, more than the cost of doing the work. If you're willing to do the work, there's an arbitrage opportunity.
If, however, the strategy is to buy a rundown house, fix it up and then re-sell it, that's slightly different. It's based on making improvements to the asset and not just hoping it magically appreciates. I used to watch a lot of HGTV and there were so many times I'd see a show where someone walks into a house and decides they don't like it beccause the color on the walls or the appliances. People are generally willing to pay a premium for houses that don't need any work, more than the cost of doing the work. If you're willing to do the work, there's an arbitrage opportunity.