"If RealPage has caused a rise in prices, it's because it showed old assumptions are wrong."
Your assumption that RealPage (and other software) -powered market is a market is wrong. Its a near monopoly and thus the price is excessive. Everybody has to live somewhere, if you double the rent of (nearly) all flats, everybody will still be willing to pay that doubled price.
To simplify it: altough there are many landlords, they arent each others competitors thanks to RealPage. They are collectively one big landlord holding the city hostage.