I know what your saying. There’s always an offbrand item that’s an exact replica of an item that sells for 2x as much. I see this a lot with electronics. I feel you do pay that extra cost just because that BRANDNAME slapped on the item like you said it’s crazy.
Well I dont think its always Greedy brand names, though sometimes it is.
In the case of Arcadia, I would like to think they do R&D products, there is no doubt their UVB bulbs are their Spec. So there was some R&D work there, then the packaging, the shipping to vendors, the vendors have to make a profit, Arcadia has to make a profit, they get hit with Import Taxes getting to their warehouses, then again shipping them out, especially as they are not a US company. Being a business owner myself, I can tell you first hand, there is a never ending amount of people with their hands out wanting "Their Cut", especially the US govt, who has you pay fees and get licenses that make zero sense and have zero to do with anything you actually do....
By the time all those hands in the pot get their Money, employees are paid, marketing is paid, ect, the amount of money John makes is likely very very low. Then the Chinese manufacture starts selling the product they made for Arcadia at a way reduced cost, thats because they are making it for cheaper than John paid, have no extra overhead, pay no extra taxes or fees outside of the small amount Ebay/Amazon take, they have their own shell company's in the US to ship to, so they pay 1 import, and pay no vendors. They are just double dipping on the product they made, and hey if they can undercut by 40% and make 3 dollars, who cares thats 3 dollars they didn't have.
It comes down to an ethics issue, you should support Arcadia if you can afford to for what they do for the community. However I am a realest and understand not everyone can, so I will still call out when a spade is a spade

. Even in my own business, when people come in and say "can you get me this" and I say ya, if its cheaper on Amazon and I know it, I will tell them that. If they choose to support me, the local business with Fees cool and I appreciate it, if not I understand. More often then not, they will appreciate the honesty and choose to support me because of it. Sometimes with big ticket items, they simply cant, the price difference is too much often with my distributor pricing + shipping to me, is more than the Amazon price shipped. I insist these people go with Amazon, but they come back for lots of smaller stuff later, so I stay afloat and they leave happy.
Arcadia also does offer a Warranty, something you will not have with some fly by Chinese Amazon seller. You got the time Amazon Protects you, beyond that good luck lol. That doesnt matter to everyone, or to every purchase, but sometimes it does.