As our fearless Master Manch would respond, there are no stupid questions. All questions by members of this forum are legit, unless you are asking about Tela Tubbies.
You are not missing anything. Some investors like to "stick" to areas where schools are already established and good. Examples would be like Cupertino or Palo Alto, where the public schools are top notch, however, the drawback of course is that the housing prices tend to follow along in step. Others like to hunt in those diamond in the rough areas where yes the current state of the schools may not be as great (at all) but may be rising. Those investors are "betting" that over time that the corresponding lower housing prices there will rise along with the school ratings. The example I have used before would be Fremont where you have a lot of young professionals moving in to those more affordable, non prime neighborhoods (non Mission San Jose) and over time of course hopefully they will help raise those scores due in part to their participation and interest in their kid's education. Tiger moms would apply here. And that was what my actual tenant told me, that they understood my home does not feed to the prime schools but they weren't concerned yet (young kids) and they felt they could impact the schools positively going forward. You are correct that no one can honestly predict exactly what will happen but keep in mind that this is only one variable. There are other variables to consider as well to help you make an educated decision on whether to buy or not. One thing for sure, there are fewer and fewer really cheap areas around here (immediate Bay Area) so chances are that those areas will probably not remain that way for long (unless, again, some real issues that can not be changed for example a house right next to the freeway or a housing project).