Companies come and go, we lost some in WWII like Houghton Butcher, their headquarters and records destroyed in the London Blitz. Many big names were lost or severely downsized in the 1961 recession, Johnsons of Hendon who had absorbed Hougthon's wholesale side during the war abandoned chemical and equipment manufacture as a result of the 1961 recession, and struggled on making amateur chemistry for a few years longer. I mention Johnsons because they supplied chemicals to Fox Talbot and went on to synthesise photographic chemicals supplying companies like Ilford, they made colour couplers and developing agents at their height.
Roll on 60 years. There have been new suppliers in recent years who have eroded sales from those that became complacent, and long-standing suppliers who keep and add to their loyal customer base. The companies that survive have bricks and mortar premises as well as good e-trading through their own websites and/or eBay.
In my 50+ years working commercially I've seen companies come and go, my main supplier currently is a company I first bought LF equipment from 45 years ago.
Ian