Scientific research is not cheap. Conducting experiments requires people, reagents, technology and a lot of very expensive equipment.
The funding for science can come from two sources, private funds (from companies and foundations) or public funds, which can come from a number of different government agencies.
In general, companies focus on specific goals, such as drug design or vaccine development, for specific diseases. Therefore, deciding which projects get funded is typically not determined by the people running the experiments in the private sector (there are exceptions to this, of course.)
In the arena of public funding - the source of financial resources for the majority of academic science - the system works very differently. Because there are more ideas...