Increased investment doesn't mean that said investment is still anywhere near enough (it's not), meaning the fact that education funding has increased isn't mutually exclusive from the fact that schools are still being starved for funds.
Indeed, when looking at
per-pupil spending, compared to other countries, we're actually ranked quite low, wedged between Uruguay & Slovenia.
Not to mention, the bureaucracy, standardized testing, & general teacher apathy caused by the profession being under perpetual assault by the broader public culture don't help, either.