That's all very well and good but you're missing a fundamental point. You're talking about what you didn't pay for, but you don't realise what you did pay for isn't as good or complete as it could've been. Despite having paid full price for the game, you're still having content gated off from you.
You said that XV DLC didn't exist when you bought the game but that's a bad choice of phrase, as it very much did exist. I was going to say what you mean is "it did exist, it just wasn't for sale" but even that's wrong. The XV DLC was planned from the start, because they announced a Season Pass before the game had even launched. Still don't see a problem? They deliberately removed and deferred sections of the game that they could've completed and included in the launch title so they could make you pay more for it.
Oh, and let's not forget they also did the pre-order bonus and retailer exclusive nonsense too. http://uk.ign.com/articles/2016/11/1...-order-bonuses Want to wait a day or two to see how the review scores are? Don't want to buy from Amazon? smurf you. I know what the response will be: Oh it's just a sword and car decal, who cares? Sure, but explain to me how this benefits you or I as fans and customers in any meaningful way. It doesn't. What it does is reduces and diminishes the game - even in a small way - for the deadly sin of daring to not utilise Square's preferred commercial partner.
Or let me put it another way. If FFVII had removed the Wutai Pagoda, chocobo racing and Cloud/Zack/Vincent flashbacks and made them DLC, and if they'd made Cloud's Nail Bat an Amazon pre-order bonus (did Amazon exist in 97?I bought my FFVII from Woolworths!) would the game be utterly ruined? No. Would it be worse? Yes.