I presume that when you find questions in this state you're upvoting the "good but slow" answers? The original asker may have accepted the fast answer and moved on, but if you're landing on the question now, it's definitely not too late to improve the content you found.
I regularly upvote older questions and answers that I find interesting or helpful. It's also fun to have my own old answers upvoted or commented on, which prompts me to go back and reread them.
