Dynamic range is extremely important and is a major difference between amateur and professional bodies, but something that is rarely discussed.
(Which Phil pointed out wasn't true, "utter rubbish".)
Which is correct [...] It's simply a technical difference between the high end bodies the vast majority of professionals use, and the consumer models most hobbyists use.
The fact of the matter is that for several years at least those using Nikon & Sony enthusiast level crop sensor cameras enjoyed (and still enjoy) superior dynamic range to the top end professional full frame Canons. For example, the Sony A77, released in April 2011, according to DXOmarks's well respected dynamic range tests had 13.2 stops of dynamic range. Until the release of the Canon EOS 5D mk 4 in 2016 Canon's top professional full frame camera, the mk 3, released in 2012, had a dynamic range of 11.7. The 5D mk iv, released in 2016, had a dynamic range of 13.6, the first professional Canon to squeeze past the dynamic range of the by then five year old crop sensor Sony A77. Alas however for dynamic range enthusiasts, that still didn't better the Sony A6300's 13.7, released six months before Canon's flagship, or the Nikon d7200's 14.6, released a year earlier, both crop sensor enthusiast level cameras. Note that I'm here comparing top end professional full frame Canon bodies with unprofessional crop sensor Sony and Nikon bodies. Their more professional full frame cameras do even better.
Of course if by "the high end bodies the vast majority of professionals use" you mean Canon, and by "the consumer models most hobbyists use" you mean Canon, then your claim is true, but rather misleading, since if dynamic range was so very important, then the "vast majority of professionals" and "most hobbyists" wouldn't have been using Canon, especially since they could have saved a lot of money while gaining a lot more dynamic range by dropping down from professional to the crop sensor enthusiast level cameras of Sony and Nikon.
I can't agree either with your claim that dynamic range while very important is rarely discussed. Canon's rather poor dynamic ranges compared to those of Nikon and Sony have been for many years an endless topic of discussion, quite possibly discussed more than any other difference between Canon image sensors and those of Nikon and Sony.
I do agree with you, however, that dynamic range is very important. As an unprofessional amateur photographer of limited budget I'm still using my aged and long superseded Sony A77, and am still delighted by its extraordinary dynamic range, so much better than anything Canon made at any price for many years, and still not much inferior to their current best.