I own the whole trio of internet brands (RE, FI, SI) and it's popular for a reason. There is great value in their products because they make them specifically and tailor to the interests of the internet car audio community. I don't remember Alpine ever asking around about what people want from their products. I don't remember a JL rep answering any questions. Polecat is the closest we have to "mainstream" and he helps out some.
The reason why these internet brands proliferate is because they have a direct connection with the customer. Could Alpine, Pioneer, etc theorhetically build a better sub than FI, SI, etc. I believe they could because of the massive amount of money they have compared to the internet companies. They are not over hyped, they perform as advertised.
And as for the weekly allowance comment, my tweeters are worth more than anything in your system.