Bussing solves racial disparity within a district, not economic disparity. Course, these often correspond but not always.
Most first world countries fund educations out of the federal budget so it is more equitable; course, the libertarians would call that socialist, but you reap what you sow.
I tried to find statistics based on state, but could not find any data. (A quick google seems to imply that CA, NY, and WA do not do it based on county, but it's hard to say that most states do with only 5 measurements.)
I'm not really sure why your posts are so angry about this topic, but your original assertion was that schools were segregated by wealth, which is obviously not how are schools districts are devised. I understand that your jaded worldview may keep you from accepting this fact.
Is there a good solution though? I've seen kids bused across town to try and fix this. Of course if you're the family who is getting bused across town to go to a worse school you're angry, but if you're moving to a better school you're probably pretty happy. Other counties have school choice plans where you can pick your school from a small list and they hope that it evens out (Hint: It doesn't).
Both options suck. What is better? Do other countries provide funding at the national level so that poor counties can educate at the same level as rich ones? In America, that'd probably require a change to the constitution.