However, Art Morris's website, birdsasart, was very influential and he was a staunch proponent of the 400 prime, and he initially ran down the zoom. But, eventually he changed his mind and went over to the original zoom.
I think a lot of people do jump to zooms when the differences in cost and comforts converge appropriately. I think even the modern 100-300 2.8 pretty much well splashes writing on the wall for any similar prime, right? Like for the same cash, more or less, why buy a 100, 200, 300 2.8 prime when all can be had for prime like quality and zoom convenience? This ever has been Canon's long term direction, I think. For good reason.
But I also have you, in my mind, as a Formula 1 for BiF kinda guy with the cash and experience. Of course you're right on how much better some options are, but does that apply to the people driving Hondas? Only while they're in the stands cheering, not once they leave the parking lot.
Mind you, he was one of the first to go to Nikon and then Sony. So, you are not right!
Haha!
For the love of life, Art — WHY?
But ya got me: Art jumped so all of those lens sales of the 400mm f/5.6 where bogus and I'm wrong.

I mean, Canon just kept pumping them out from 1992 through 2022 because they were bored and stuff.
The first version bettered it
But so marginally in terms of the mark I, and who shoots animals or people in the lens corner? Kind of like maybe this truck tows more than that truck in the same class, but then one might also consider sway control. Even with the zooms available and evolving rapidly. And even when the II came out big names still talked-up the prime for beginners. Some examples:
The Digital Picture maintains this statement:
The Canon EF 400mm f/5.6L USM Lens is popular for bird photography and especially birds in flight as it offers lots of reach for a reasonable cost in a relatively light package. Good vignetting performance helps keep even blue skies as they should be - evenly blue. Other uses include general wildlife photography and well-lit field sports.
Honestly, if you're just dipping your toe into animals (maybe birds, could also be deer or mountain climbers) then these lingering endorsements of yesteryear are more than enough to justify a minimal investment at the time (new) or now (used). If people like what they see, then they know spending the cash on the DO, or zoom, or a new RF lens would probably give them smiles.
the magnificent EF 100-400mm II rendered it totally obsolete.
Well, yes — but that didn't stop people from promoting the prime for beginners. Let's consider:
The 400 f/5.6L has been in the Canon lineup for 5 years longer than the original 100-400 L IS, yet it is a good performing lens with image quality essentially equivalent to the 100-400 L II and less distortion (compared at 400mm). The 400 f/5.6L is lighter, longer and considerably less expensive [...] I find the zoom to be a far more useful lens.
Bold emphasis is mine.
This lens fits in even my smallest and lightest travel kit, and I have confidence when using it wide open that it’s going to give me excellent performance. Sure, I’d like it to be an f/4, but the extra weight and bulk wouldn’t be welcome. [...] I definitely miss Image Stabilization, and wish that Canon would re-issue this lens with IS, but since I will be using it tripod mounted 90% of the time it’s no real hardship.
Forgotten 400 - Luminous Landscape
luminous-landscape.com
And just because I wanted to know, we tested the old, but excellent
Canon 400mm f/5.6 L prime lens, for comparison. Few people shoot it anymore, but there’s a reason it’s remained in production for decades. It’s not quite as good as the 100-400 IS L, but still, an excellent performer considering how old the design is.
I get asked a lot about different telephoto lenses. Is the 400 DO II better than the 400 DO? Which is better, the Tamron 150-600mm or the Sigma 150-600mm? You've probably noticed that I don't answer those questions. The reason is simple. Our optical bench is designed to test lenses up to 2.5kg...
www.lensrentals.com
The 500/4.6 was OK for BIF when you are at 1/3200s and don't need IS. But for hand held shooting in other than good light, a tripod or support was essential, and if you have ever tried to focus a hand held 400mm lens without IS, it is very difficult as the image darts all over the view finder.
I 100% agree with you about the hassle and comforts. And cash being no issue your argument wins every time.
But if you put the two lenses on the table in front of my kid, or someone still in university, or someone buget limited and they read all of those reviews I bet they'll buy the cheaper lens each time. Or, at least 95% of the time. Sure, eventually they'll buy a 600mm f/4 if they get the bug for shooting tiny skittish things, but probably not up-front.
And I think this gets back to the point of what a 500mm 5.6 represents: an affordable way to get quality images of "distant" things that need to be magnified to fill enough of the frame in a daylight situation. Most people will be happy with that. Some will realize f/4 or f/2.8 matters and spend the extra cash — but only after being really sure about that. Sigma showed this option is not just viable, but pragmatic. A silver ring edition from Canon will probably make a relative killing over decades.
And let's not forget: yes, the lack of IS (or useful IS) and need for daylight can be a hassle, but that never stops a determined person.

