My big takeaway from that video is that he would seriously have to adapt his swing to put the ball in play consistently with the old equipment. I play vintage equipment/ hickory clubs on the side- maybe about 10% of my rounds, but I don't swing like a modern bomber. So, I don't have to do much differently to go back and forth.
However, he and most other modern players, really do rip at the ball something fierce. And it makes sense, because they can miss it all over the huge sweetspot and get acceptable results. The shorter shaft, the heavier head, and a more deliberate swing would take a 120 mph swing speed down to 105 I bet in a tournament setting.
So, in that respect, it isn't so much about max distance, it is more about consistent distance. It matters far less how far someone can hit their best drive when it brings so much risk into the equation. It's why nobody is afraid of the long drive guys in a golf tournament. They may hit it 400 yards, but that is a 1 in 5 shot and the rest are off the grid.
But imagine him standing on the 18th hole at Sawgrass with a 1 shot lead. Or in a Ryder Cup environment. A pop up is not completely out of the realm of possibility. A snap hook, a heeled slice, and many other horrible outcomes are likely with an overswing or a nervous swing.
Greg Norman would have been such a killer with modern drivers.