That's exactly the problem, "meaning in life" has no static definition and there is no possible way to explain it in general terms, even for people who proclaim to have "found" it.
Pills, on the other hand, are easy to understand. This is not to say that they are a viable substitute in any way, but it does explain why so many prefer substance treatments.
Meaning in life is hard and personal. Some might have no idea where to start.
But I'd argue (somewhat pointlessly as I'm not going to change anything) -- This is the role that society, traditions, family, etc. has: "to bring people up" swimming in the same stream, given a purpose and meaning, etc.
Pills, on the other hand, are easy to understand. This is not to say that they are a viable substitute in any way, but it does explain why so many prefer substance treatments.