I'm not going to beat this to death either, but I'm talking pricing in 2016 vs 2020, so my comparison is not as far back as you figure it is.
Base price for a GT350 in May 2016 was $52k, $94k for a base GT500 in Aug 2020 is close enough to double for me within a four year window.
Granted, 2017 saw that base go from $52k to $62k with the added coolers and such....I lost touch with the pricing, so I didn't see the base climb to $76k, got me there. The GT350 isn't on the ford.ca Build & Price anymore, so I'll take you at your word as an informed source.
When I considered buying in 2016, it was at the limits of what I could do, so if I was faced with making the same decision today, theres no way in hell I could pull off $150k for a Mustang, no matter how good it is. I'm really fortunate that I bought when I did, and got the car I did for the money I paid.
The GT500 is good, maybe better than the GT350, but I don't think its twice the car for twice the money.....
This could turn in to one of those back and forth debates, so I make my counter points respectfully, as adults and enthusiasts with differing opinions having a spirited conversation about the cars we love. I've found during my time here that your input to this site is always informative and well spoken, so I'm not interested in sniping back and forth.
In the end, with the trickle down effect of the different parts used in each model to the GT and such, we all win.
I give full props to anyone who can enjoy the GT500, I'm still waiting to hear the whine of that supercharger under the hood of a Raptor.
Then I'll pay $150k. lol