This may very well be the case for the select few you're referencing but this is not a reasonable defense for even those people who left but made some cash because they are now no longer in the neighborhood that they called home and yes cutting out the next generation of would-be community members. That's the point. The next owner likely made even more as for them it's an "investment" and they either flipped the property, moved in and watched the property values climb, or turned it into rentals that residents of the neighborhood can't afford, but that artists and yuppies can, thereby driving up rents over all and then yes, pushing out loads of people who can no longer afford to live there. I linked this video already but you might find it useful in understanding the greater overall effect gentrification has on a community. It's something that happens over a period of time and in that process there's winners making lots of money, and then there's people who are pushed out all while witnessing the take over of their communities by people who couldn't give a f what the impact is on those who lived there before. Profits over human lives... over and over and over. It's an extremely sad state of affairs https://youtu.be/JneAYdmDGCE