If you really want to geek out get DeLong's guide to bicycles (1974).
In general if you want to find out about Vitus, it's probably more fruitful to search for the original name of the company, Ateliers de la Rive.
I think they rather forgot their origins when they went into aluminium and got bought out by Look (Bernard Tapie?).
Not so much that as commercial realities. Reynolds and Columbus brands overtook them. Even Peugeot dumped Vitus steel in favour of Reynolds.
The aluminium thing was an off-shoot with Bador, and was a small part of what was essentially a packaging manufacturer. They changed hands many times in the 90s, Time owned them too. I've no idea if they exist any more other than as a brand name for CRC. I'd be amazed if they produce anything.