I think those beautiful bottles add to the enjoyment of dosing. 😉 Besides, many people can definitely pay for the hobby and as you guys know, the salty water people pay like crazy. Some of their products are hideous!
I do agree about DIY etc and I was the first one in Australia to sell a all-in-one fert for aquariums, after seeing ridiculous prices elsewhere by many other companies. Seachem were still doing their silly little bottles with useless ferts and no nitrogen!
The time needed to learn how to fert properly is money to some people. Besides some will only remain in the hobby for 2 years or so. I think they deserve beautiful bottles, aquariums, glassware and the whole lot; especially if they are happy to pay. They don't need to mix chemicals or browse through 100 page documents on how to mix your own ferts. 🙂