1. Short answer, no.
Long answer, it has been pointed out constantly we are far below the average PC wealth as defined by the DMG for 7th/8th Level PCs. Not only that, but the most expensive items we ever got were a pair of swords, one +1 Frost the other Flaming. We had it shipped back to the shop so it could be sold, or at the very least put on display so it could bring in a crowd, because it was possible they could be weapons of a legendary dragon slayer.
However when we returned to the shop, we discovered a powerful assassin buying the swords. Sure, he bought them at full price, so no problem there, except they were sold to cover debt the shop supposedly incurred while away, leaving a profit of 4000 GP (a debt number decided upon before even figuring out how my shop would work). Keep in mind other items were sold while we were gone as well, including four Rings of Protection +1, four +1 weapons, and many other items.
So on top of trying to figure out what to do with the shop so we can actually get some wealth, we have no wealth to work with throughout the entire time. The DM also "sold" our treasure with not even an 1/8 of a return, including the most powerful weapons we've ever come across to an Assassin who is now even more powerful because of it. So no, I don't think he can handle the wealth level to make it fun for us, because he doesn't give us anything to begin with.
2. I'm a little appalled by this question, but I'll answer as best I can. Making and running a magic shop is a
goal of my PC, one which he will not stray from. He has pride for his craft and his people, whom he seeks to elevate through this task. As a Player in his game, the DM should find a means to facilitate this goal I seek,
regardless if he doesn't think it's fun or worthwhile.
Don't get me wrong, I'm not obsessing and focusing just on the shop in regards to the game/campaign/what have you. It is merely the focus of discussion on this thread, and a hurdle that after two months has still not been resolved. I
want to get back into adventuring, discovering mysteries and shaking the foundations of the earth, which I think/hope the DM wants to do. This shop? This is a
thing in the game, which I hope will supplement the future gaming we do. But we are stuck until that can actually be figured out.