There's too many people to reply to so I will say this.
Floyd is second to none the greatest defensive fighter of all time, and top 5 boxer of all time IMO.
Sugar Ray Robinson
Muhammad Ali
Joe Louis
Roberto Duran
Floyd Mayweather
At around age 28, Floyd was fighting Gatti and Judah and was rising in the P4P rankings. His PPV for the 3 fights against Gatti, Judah and Baldomir were 365,000, 374,000, and 325,000.
Floyd was an up and coming fighter until he fought Oscar De La Hoya on May 5 2007. This fight generated 2.4 million and Oscar was the biggest star in boxing at the time and of all time. Oscar De La Hoya was 90%+ responsible for the PPVs and without him, Floyd would not have been as big of a star.
Conor is way more successful than Floyd, at around the same age. He has beat Poirier, Mendes, Diaz, Aldo and Alvarez.
Eddie Alvarez is one of the greatest LWs of all time and has fought all around the world. The Chad Mendes that fought Jose Aldo was a P4P top 10 fighter IMO and is one of the best fighters to never touch UFC gold. Poirier is a good fighter that has competed at the highest level since his early 20s. Nate is a UFC veteran and one of the toughest fighters in the sport.
Jose Aldo is a P4P top 5 fighter of all time and never lost in nearly 10 years. Floyd has never beat someone as good as Jose Aldo, not to mention Conor beat him in 13 seconds.
Floyd is a legend, but Conor was way more successful at the same age, becoming a 2 divison champion.
Conor's PPV at the same age against Mendes, Aldo, Diaz 1, Diaz 2 and Alvarez are 825,000, 1.4 million, 1.6 million, 1.65 million and UFC 205 estimated is about 1.5 million.
Floyd is an absolute legend but Conor's stardom is higher at the moment and he has achieved a lot more than Floyd at the same age. Obviously if you look at it now, Floyd has finished his career, who knows what Conor's career will look like in 10 years but the way it is trending now, I have no doubt he will be one of the greatest if not the greatest.