Maradona's peak lasted 5 years at best. Joined Napoli in 84 and was already past his best in 89. If longevity was so important, he should have no business being in the same tier as Pelé and Messi. And Ronaldinho wouldn't even belong in the second or third tier going by this.
So to me, R9 absolutely belongs there because of his peak.
Maradona was actually very good prior to 84. For example he moved to Barca in 82 as world most expensive player, there was also very high expectation on him in 82 WC too. Prior to that, he was South American player of the year in 1979 and 1980, which is not easy feat as he has to beat the likes of peak Zico, Socrates, Kempes to win that, which means he has to be playing at world class level at the very least. He also scored 43 goals in 45 games in Argentina league in 1980. So I'd say his "world class years" span from around 1979 to 1990, thats over or around a decade.
1979 - Won FIFA youth WC with Golden Ball. South American player of the year
1980 - scored 43 goals in 45 games in Argentina league. South American player of the year
1981 - Argentina player of the year. Include in world all star team. 2nd in SA player of the year, losing to Zico
1982 - already well established as world class player, move to Barca for world record fee. 3rd in SA player of the year, losing to Zico
1983 - Include in world all star team, during his most disappointing time at Barca, stills scored 23 goals in 35 games in La Liga.
1984 - move to Napoli for world record fee again, entering his peak years, include in world all star team
1985 - peak years, include in world all star team, Serie A footballer of the year, won Onze award (European player of the year)
1986 - peak years, won WC with golden ball, won every individual awards he is eligible, won Onze award
1987 - peak years, won Serie A, won Onze award
1988 - peak years, won Onze award
1989 - peak years, Serie A top scorer, SA player of the year, won Onze award
1990 - last of his peak years, won serie A, SA player of the year
No way Ronaldinho or R9 has similar length of worldclass years or peak years as Maradona.