That’s hilarious. Better phrased would be “GM wasn’t able to fix the oil leaks so Rover bought the design.”
It would be funny if it was a joke, this is the same GM that changed the color of their orange grenades(SBCs) to black in the 80's to reduce the number of oil leak complaints- if the customer doesn't see the leak, they won't complain.
My friend had an XKE in the very early 70's, he called the Jag dealer in Manchester because it was leaking a quart of oil a day, they said that was about normal.
I rebuilt an MG Midget we took in trade on our first 81 Escort because the dealer's 6'2" tall son wanted it. When he drove it he looked like a monkey riding a football. There was no rear main seal in the engine and no front seal in the transmission- both used oil slingers. If he parked it nose down a hill, the trans leaked, nose up a hill the engine leaked.