There is nothing at all wrong about liking the way your mod looks! But yes, it is your fault for buying a clone when the original is available, even if the only thing you like about it is it's looks. That is the essence of the argument. Getting that look took effort, time, money, knowledge, education and creativity on the part of the designer. That's the key misunderstanding with clone buyers. That "look" has value. To them it's like saying "Why should I buy a copy of Windows when I can just copy my friends for the cost of the disk? Bill Gates is just ripping me off!" They have no idea of the hundreds of thousands of man hours and dollars spent to produce each new version before MS ever makes a dime from it. The same holds true on a smaller scale for mod makers. I would guess the vast majority of clone buyers have never created anything of value or brought any product to market, they go into buying with the narrow mindset of a consumer which is "Get as much as I can with as little money spent as possible" rather than considering the actual costs involved with doing so. And that makes great short term sense but in the long term does nothing for maintaining or advancing the market. Making a clone requires much less effort and is much more affordable and while it grows the industry in the short term, in the long term it hurts product advancements.
For starters there are free alternatives to windows for those who feel that Bill Gates is ripping them off (or whatever reason), Linux for example, along with a lot of other 'open source' software. Open source software has been created by those who feel that software should be free (including products similar to photoshop etc) and not just available to those with money.
The factors you list as the input for the end result of creating a good-looking mod are a little far fetched. Admittedly some manufacturers (as I have stated before) create from the ground up, innovating to create solutions to the problem of 'how do I get power from a battery to an atomizer', but the vast majority of mod manufacturers simply use an existing mod design and slightly change the aesthetics. This requires no engineering ability whatsoever, the only part that requires some skill is turning their 'new' design into a CAD file (or whatever format). Then obviously the CNC programming (which is unlikely to be done by the designer).
I could list mods that follow this pattern, but it would be a waste of time, I will just let you check out the 'variety' of mods when you next look at an online vape shop.
The look is indeed what people want, the performance is a secondary concern for the hoi polloi.
We know that people will pay what they think the product is worth to them, so the problem lies with the manufacturers that charge the premium price despite their product being neither innovative nor premium quality, but they feel they can charge the price due to other more worthy (of the price tag) manufacturers charging it. It becomes the 'going rate' for original mods.
This is the problem and is why people (clone buyers) feel like they are being scammed, it is not ALL the manufacturers, it is the ones that hike up their prices undeservedly, it is like Honda trying to sell their cars for the same prices as Ferrari.
As for the 'hurts product advancements', I feel that it does the opposite, it encourages designers/manufacturers to come up with NEW designs, innovations etc. Most of the Mod makers create their mods in small batches (as a reduced risk), these batches sell out, then they move on to their next mod, they don't plan on releasing more of the same product because it dilutes the exclusivity of their mods and therefore would lower the desirability (in collectors' eyes).
I realise that some manufacturers do continue to manufacture their mod/mods on a regular basis, and these are the ones that are actually worth the price, they are not cookie cutter mods.