Oh it's certainly not all marketing. My examples of specific products from Icon, semi deeps, the wrenches, that's most of what I would be directly interested in looking at. I considered Icon when I wanted a different ratcheting wrench to replace a set of gear wrench I had used for ~10 years. And a coworker bought a pretty nice set of 1/4 extensions and I'm picky about extensions.
On the one hand Icon offers a functional product, with some level of quality that's totally acceptable, which is cheaper than the moon-shot pricing of Snap on, or Proto, or Wright. As your post reflects, I can buy Quinn sockets in the very same HF store, or even my favorite the multi-colored sockets which are sadly not 6 point in all sizes. So while the usual suspects at the tippy top seem to be consistently the best, they have a very high price associated. If we cull the top of the market, let's call Icon the most premium brand available just for discussion. Why would I buy a $40 set of Icon 3/8 deeps, when I can buy a good set for $12 from Pittsburgh Pro? Yes the Icons will have the better necked down profile on smaller sizes, however my preference is not having graduations of size like Icon or Snap On, rather having the sockets be identical in length like Pittsburgh Pro. Icon deeps "compare to snap on" are 1/7th the price, 327/45. 327/$13 Pittsburgh Pro is 1/25th.
For many considering Icon here, it seems like there's a "why buy premium brand if I can spend 1/4 and get a quality tool"? Well that sort of wraps back into Icon in my mind, when the Pittsburgh Pro sockets lasted me in the rust belt many years of daily use with good performance. Are my Williams better? Yup. In my mind the mentality which sells Icon to me over Williams, then makes me buy Pittsburgh Pro. That's why I always say I don't understand this middle step between "buy it for a life of use" and "buy it to do the job and minimize cost". Certainly some part of that is my own mentality and doesn't apply to everyone. The extreme version of this is buying all tools from TYBHN56M brand on Amazon which I think gets a bit short sighted. At least with a "known" brand there's some level of consistency expected from the product and hopefully you can rectify a problem easily if it happens right after purchase. The plus side with Icon to me is the easy availability of a product locally which is needed in some areas the cheaper stuff just kind of *****. Extensions in chrome, being a great example I'd say Icon seems like a good choice. Or chrome semi-deep sockets in general, not super common, Icon was smart with those. Now Icon did goof with not adding a significant undercut to aid removal of the sockets, too busy chasing snap on aesthetics. Snap on finally added that undercut, but only on FDX sockets which aren't really usable as daily drivers IMO if you're in the rust belt.
FWIW I hate the Icon/Napa/Milwaukee toothed end. ***** balls IMO. I bought into the Napa Carlyle hype when I first got on here, and those wrenches performed pretty poorly for me. Soured me on the brand entirely, but luckily it was an SAE set so I didn't suffer with it much for the couple years I had them before I traded them.
Please nobody read into this as being anti-HF, anti-Icon, anti-whoever. More options = more better.