It's not easy for sure. That said do you put guys with titles whose prime production was in a short window as a priority over guys like Melo who did it over a longer career?
I don't think it is as easy to say no way is he a top 30 player. He was an elite scorer overlapping two to three generations of NBA stars. People have their favorite players like McGrady and Penny amongst other guys who had some great seasons and also got titles despite much lesser statistics.
So if we take tenure and longevity out of the equation you would massively upend the top 75 as it stands today. More than a few guys had incredible years and were unstoppable some with more playoff success. Then you have the guys that were high level for a long time and have massive stats.
Another way to do it is simply make it clear who the GOATs are. Wilt, Kareem, Jordan, Bird, Lebron, Duncan, West, Kobe.
Can argue on maybe a couple of other guys on that top level(Shaq, Oscar, Erving, Etc). After that you then start looking at what you are going to prioritize to rank the next 30-50 guys. It's absolutely not cut and dry, depending on how you prioritize as to where Melo should or shouldn't fall.