It isn't especially hard to develop drugs for genetic diseases.
For simple genetic diseases where an uncomplicated biochemical mechanism has been knocked out and you know how to fix it. We don't know where even to start for intelligence.
Here is a different angle of view on basically the same problem: after people turn 60-70 years old, they start to become stupider and it's a fairly rapid and continuous decline. Why? We don't know. How to fix it? We don't know.
Harvard's current admissions website boasts that it provides no merit-based financial aid.
You misunderstand. Harvard, being a very rich and a very prestigious school, has a what's known as "need-blind" admission. That means that if they accept you, they will find money to pay for your education even if you're dirt poor. They will not turn away anyone who got accepted but doesn't have the money. Given this, there is no particular need for merit aid.
I'm curious about your claim that at 60-70 years old people start rapidly becoming stupider for reason we don't know. I thought that I recalled reading that while the various forms of dementia become immensely more common with age, those who are fortunate enough to avoid any of them experience relatively little cognitive decline. Unless you mean only to say that our present understanding of Alzheimer's and the other less common dementia disorders is relatively limited, so you're counting that as a reason we don't know (it is certainly something we don't know how to fix, so you win on that point).
It's great to make people more aware of bad mental habits and encourage better ones, as many people have done on LessWrong. The way we deal with weak thinking is, however, like how people dealt with depression before the development of effective anti-depressants:
The only "anti-stupidity drugs" we have are nootropics. But the nootropics we have weren't developed as nootropics. Piracetam was, I think, developed to treat seizures. L-DOPA was developed to treat Parkinson's. No one knows who started using ginkgo biloba or what they used it for; it was used to treat asthma 5000 years ago. Adderall derives from drugs used to keep soldiers awake in World War 2.
And none of them are very good against stupidity. AFAIK, to date, not one drug has been developed by understanding and targeting the causes of different types of stupidity. We have the tools to do this--we could, for instance, sequence a lot of peoples' DNA, give them all IQ tests, and do a genome-wide association study, as a start.
We don't research these things because society doesn't want to research them. People don't conceive of stupidity as a disease that can be cured. We need, somehow, to promote thinking of stupidity as a mental illness. As something drug companies could make billions of dollars off of.