Come on now. People need to stop with the history revision. No one knew that Ronaldo would turn out to be the player he is today at age 19 or 20. He was behind the likes of Van der Vaart, Torres, Robben, Podolski, Rooney when it came to top players in and around his age group. He was fast and tricky yes and had good potential, but so did Quaresma. It's as if it was abundantly clear that Ronaldo was going to be one of the greatest ever or even of the last decade, it's simply untrue and smacks of retrospective adjustment of opinions.
Ronaldo was excruciatingly inconsistent, had ridiculously bad decision making, was a bit of a selfish prat, was labelled a big game bottler, dove on every occasion, hadn't developed his rocket free kick technique, didn't even score a European goal till age 21, did nothing when we got steamrolled by the likes of Chelsea and Milan and crashed out of the group stages in 2005/ 2006 - finishing 4th behind Benfica, Villarreal and Lille. It wasn't until the 2006/ 2007 season that he really started to assert himself as one of the top players in the game.
Different players have different growth curves. Some of the players who were considered better than Ronaldo at that age stagnated or didn't progress beyond a certain level. Others who weren't rated as highly as the absolute top young talents - the likes of Ribery, Van Persie, Suarez have developed into better players than Podolski or Torres or Reyes or Van der Vaart. Januzaj has a great chance to be that caliber of a player. Someone like Kaka was going to be loaned out by Milan at age 21 in 2003. It was only because of Rui Costa's weak form that Ancelotti kept him in on and he developed into a Ballon D'Or caliber player in the space of a few seasons which shows that footballers can develop rapidly and that growth isn't linear.
Young footballers are dismissed very easily these days just because of a few poor games and because they are compared to X, Y and Z players who are all finished products and we have the benefit of hindsight. Was Zidane Zidane really Zinedine Zidane at Januzaj's age ? Was David Villa the finished article for Gijon's B team ? Was Van Nistelrooy when he was playing as a central midfielder for Den Bosch ? Was Vieira when he couldn't even break into Milan's senior team at age 20 ? Januzaj needs time to develop both physically and mentally. He is still very young and needs the right environment to thrive.