That's the way it's always been. Modders are free to use higher polys, for cc hair and clothes etc. Some don't pay attention to the faces/verticles and polys, until they start to lag out the game. lol Maxis has a rule to stick to lower polys for things like hair. Sims walking around with 35,000 polys of cc hair all day, every day, is too much of a strain on machines. Then think of that hair and if it is townified to where all the Sims in game could be wearing it. Performance issues do influence what is high poly or low in any game. As far as modders creating mods people like to use, it's always been that way. To remove, improve or totally change a game. I'm not sure I agree with you about Maxis should be ashamed. They have a route they have to follow, not sure I agree with their 'vision' about TS4 but modders have been where to go when you want something to work differently or even add custom animations and situations.
Even Will Wright was amazed by what content creators and modders could do way back in TS1, and would download player content (mods and cc) and try them out and play the game with them installed. lol It's no shame for Maxis, in my opinion , that modders can make some amazing stuff and mods/hacks but it does matter if they don't (or wouldn't) make the game more modder friendly to players.
