I dunno, a +3 enhancement on a weapon costs 18,000 gp, and the earliest you could possibly have that based on the wealth-by-level chart is level 7, and that's if you have literally no other items to your name. Consider how powerful a person at level 7 is compared to most NPCs in the world and it makes sense that it's absurdly difficult to find a sword with a modification like that.
So, imo, I don't see anything changed with the wealth-by-level chart, especially since that chart assumes that you amass things like more mundane items and wondrous items, perhaps a little bit of property and followers on the side depending on the character (especially since the delicious Leadership feat is 6th level), a character really shouldn't expect a +3 weapon until around level 9 or 10 at the absolute bare minimum, and even so that's assuming the character isn't absolutely decked out in other equipment.
Perhaps I have different DMs than you, or maybe I'm just a different kind of DM myself.