I'd guess the majority of those success stories are invisible to the end user.

e.g. simply keeping the company afloat via PE cash.

If I recall correctly, this is what happened to Hilton Hotels. They were collapsing during the housing crisis.

A slightly different scenario but Hertz is a PE success story. It was owned by Ford and bought by a private equity firm. Now it's a standalone company making mint.

Were those roll-ups though? I see a poster below says the private equity fund was only involved for the last acquisition, but no one can deny Muse Group/Ultimate Guitar went on a shopping spree. They looked like they were trying to gain control over a whole segment and start squeezing (well, except for that open source projects aren't that easy to squeeze). No wonder people freaked out over the telemetry, it was reasonable to fear the worst. But everything went better than expected.