Rock climbing has a history as a technical part of Alpinism. Over time, some people started to enjoy rock climbing more as a sport, and as an end unto itself, instead of just a sub-skill contributing to mountain ascents. Early 20c rock climbing started to break from the traditional siege mountaineering techniques: fixed ropes, jumars, hammered pins, hooks, etriers, nailed boots, etc. Post war, the availability of nylon, aluminium, chrome-steel, and synthetic rubber opened up the possibilities. Modern big-wall, ice, and clean rock styles developed. Chouinard was part of all these scenes, and big proponent of style. He made equipment, put up hard routes, and evangelized. He was one of many founders of modern "clean" style, using dynamic ropes and clean pro, leaving "nothing but footprints.

Many early climbers made their own gear, or bought from a climber who did. But Chouinard (with Tom Frost) really got into it, and improved or invented a bunch of things (e.g. Hexcentrics, the modern ice axe, and then camalots!) that made clean climbing possible and safe(er). Chouinard equipment was from the future.

But then the 80's happened, and the diy hippie scene gave way to the lawyers. Some people (novices, window washers, and other untrained people) died when they failed to secure their harness and fell, and the lawsuits looked likely to sink them. You'll notice the colour warnings and liability label around the double-back buckle these days -- that's from these suits. But, ever classy, he declared bankruptcy, sold the hard assets to the employees, and walked away. The logo and his name was consumed by the lawsuits, so the new Black Diamond logo was born. This image[0] shows two Chouinard logos, and then the BD logo. My old harness has the left logo, and I still have an old fimo earring I made to match. No offence meant to the BD people, but their logo will always be wrong to my eye.

The wiki does an ok job with the basics[1], but it doesn't catch the mood of it. I started climbing in the 80s, coming up in the Yosemite school. We were absolutely scandalized that someone could try and sue when climbing went wrong -- especially for mis-use of the gear. Self-authority was central to the scene. Smarter people than me also knew there would be all sorts of secondary problems, and the battles over access in the next decades often had liability concerns at their core. It was the end of an era.

  [0] https://www.gearx.com/blog/wp-content/uploads/2014/05/shirt2-300x195.jpg
  [1] https://en.wikipedia.org/wiki/Black_Diamond_Equipment#History