15,000 per student is not "endless resources". To put it in perspective, it's less than half of what is spent on a student at an elite prep school, which I think is a more reasonable model for what cost-is-no-object education would look like.
But let's agree for the moment that not every student needs to have class sizes of four or five with a PhD instructors. I'd be very happy if every a typical student in Baltimore has $15,000 spent on him.
There's one big, fat problem with simply saying "OMG we spend $$$$$ on every student!"
Most schools spend that money nowadays on more than just teachers, facilities, and equipment. In fact, those three are usually the categories which get the scraps. The lion's share of the money goes towards administration, counselors, and most of all, to "specialists" - which is another term for a middle-management make-work position.
30 years ago, a typical large-ish high school (let's say ~2000 students) would have 40-60 general teachers, a vice principal, a principal, a couple of janitors, one or two facilities people, and maybe a small handful (around 10) other staff to handle attendance, records, counseling, etc. So you'd have a ratio of 60 teachers to maybe 25 staff for that school.
Nowadays, you still have 60 general teachers, but now you have 20 special education teachers atop that, about 5-10 ESL teachers, 5-10 special education "specialists", 7-10 counseling staff, 3-5 "curriculum specialists", about 3-4 middle managers that act as layers between the teachers and vice principal, 3-4 teacing specialists (for state testing standards, PSATs, etc) a full HR staff of 10-20, a union steward, a certification/CE specialist (for the teachers), an IT department of sorts with 1-2 people in it, etc etc etc... roughly as many (if not more) staff as you have teachers.
Oh, and did I mention that whoever runs the local school board in a larger town can rake in as much as a typical CEO, often more? For example, the Portland School District Manager in Portland, OR shovels in a salary of around $150k/year, and an additional $75k/yr in bonuses and benefits...
Long story short? Until they clean out the $#@%^! cruft, throwing more money at the problem will only mean more make-work jobs that do approximately nothing for the students, the teachers, equipment, or facilities.