So it would be useful if only the OP could mark the question solved.
I think that would result in more solutions not being marked correctly than recommended posts not being solutions. It used to be that way but as a frequent poster I can say it was getting very frustrating to post maybe 50 times per day with what was probably at least 66% of those being de-facto solutions and getting 20 points at the end of the day. Maybe it isn't as bad in some of the "pro" fora or fora where savvy users ask questions, but in certain fora where people ask questions such as how do they turn on their iPhone you don't see many users getting to the tech level of expertise required to mark a post. 🙂
Yes, you see boilerplate responses but that does not necessarily mean they are not solutions. You also see many cases where the OP has apparently abandoned a topic and not responded if the problem was solved. What is likely to be the solution is there but you never hear from the OP again. I know on the occasions when I am looking for a solution I tend to first read topics marked as solved so having abandoned ones with solutions marked as such is helpful. Again, many, many users do not mark posts. Unfortunately "helpful" does not have an icon when browsing a forum line and many users will only mark a solution as "helpful" so again those go missing when specifically looking for solved topics.
Then there's the solutions an OP doesn't like. Many people do not like "No, can't do that," as the answer to their question even if it happens to be correct. Kind of along these lines are solutions that the OP might not like but somebody else may. I tend to provide "teach a person to fish" answers and others may provide a "click here" link answer. Both have the solution and if marking solutions is the point of Apple Recommends then the OP's personal preference for response style is unfair to others.