I certainly feel for you. I'm rather picky about my own money, plus since I'm an accountant, I also understand the math behind spending and saving, etc. I learned how much things add up by simply keeping track of them.
I understand the package this. I like opening packages as well. I'm also a gamer, so I understand the gaming thing. In fact, part of the fun of a new game is just opening it. I also think everyone needs to have their hobbies and that a certain amount of money should be allocated towards entertainment, for the sake of one's sanity. And I also DO think people should get a pat on the back for doing what they're supposed to do. It's no different than wanting your boss to say please and thank you, even though it's your job. So I have to disagree with you on those items.
(What he spends his "fun" money on is not relevant, though you are making it sound like it is. People always think something is a "waste" if they do not understand the interest in it. I'm sure you have an interest in something that he does not understand either. Though I'm not referring to the junk that gets thrown away in 3 days. Obviously there was no real interest in that.)
But that said... there also has to be a limit. Like I have plenty of "me" time, I have hobbies, I have computer games, books, movies, etc. But I don't spend a lot on them. There's a such thing as bargains regardless of what it is. (Console games are expensive. I play PC games, which I can get for much cheaper, sell on eBay when I'm done with them, and I don't buy the newest thing out at full price. There's ways around the costs of things like that.)
So I don't have an issue that he has his hobbies. But everything, groceries as well as hobbies, have to be budgeted and watched out for. The "reward" should be in getting to do something fun, not in spending the money on it.
I can give people all sorts of advice on how to save money, but not someone who refuses to listen. In terms of making him understand, you might have to actually put some numbers together and show him the results. I don't know whether he truly doesn't get it and seeing it would help, or whether he's so stuck into his beliefs that he'd manage to find a way around anything realistic that he sees. But you can try that.
That is, quite literally keep track of everything spent and show him what it adds up too. Work out the interest on a credit card and show him what it costs after five years. Work out what something can be worth in the future when it's saved and invested. (i.e. if you leave it alone, look what it can grow into, versus, if you leave it only for 2 weeks and spend it, it's still gone). I can help you with the math there.
However, I'm suspecting he's just too darn stubborn to pay attention to such things, especially if he grew up with that mentality. Besides, the government teaches us this is OK as well... not only their spending, but they teach us that they'll always be there to take care of us instead of us taking care of ourselves. (Although the past couple of years should have taught him that getting into debt and such is not good.)
If you seriously think it's more about a shopping addiction than just lack of understanding, you can visit the addiction board:
https://www.askmehelpdesk.com/addictions/
When people have addictions, no amount of logic is going to matter. You have to find other ways around it. If it's seriously a problem, it might even take counseling.