One reason is they (the NIH/CDC/FDA big pharma etc) wanted to advance the mRNA platform. It has been around a while but no drug or treatment or vaccine has ever been approved based on this technology. They are hopeful the platform can be used in the future for many different types of diseases and wanted to see it put into practice, basically making everyone a guinea pig for long term safety and efficacy and sacrificing those who needed treatment for the ‘greater good’ of advancing mRNA tech.
If it were widely known that you can just take $20 worth of cheap generics and clear the virus in 10 days, nobody would sign up for the vaccines and it would be hard to even maintain the protocols for the trials that were used to approve them. If everyone in the trials who got the virus knew they could take Ivermectin+ they would drop out of the trial and take the pills - thus ruining the trial. So they needed to put the kibosh on all potential treatments in order to advance the vaccine pipedream.
Of course, you could also add political motive and financial motive into the considerations. I don’t think any person could have really done that much better than Trump, but his biggest mistake was not pushing back harder against the Administrative State and spending the money to research treatments. Even today, 20 million unresolved cases of Covid-19 in the USA what good is a vaccine for those people?
The massed artillery battalions of the Uniparty Media, wheel to wheel, would have unleashed fakenews hell on him.