First off, I don't think we need to be arguing about whether the Suns are better than the Knicks or vice versa. This league is big enough for two mediocre teams.
As far as the future is concerned, it's difficult to argue that the Suns' outlook is better than that of the Knicks. For the sake of analysis, let's just ignore the current rosters, contracts, young/developing talent, etc. for a few moments, and let's examine the respective attitutudes of each team's management. The Knicks are willing to take calculated risks; the Suns very clearly are not. The Knicks may not get Carmelo Anthony or Chris Paul, but they have a desire to - even if it means (gasp!) dolling out max-level dollars for four or five years and (double gasp!) structuring those contracts the way contracts are structured in the NBA - which, as Amar'e pointed out, is different than the NFL.
A lot of people like to point out - I think legitimately - that Amar'e's past microfracture surgery makes it somewhat unlikely that he'll be able to perform for all 5 years of his contract. While I don't know about the validity of the rule of thumb about microfracture surgery needing to be re-done every five years - luckily, I think this idea has its roots in some statements that certain members of the Suns medical staff said, and they are always completely wrong about all things post-microfracture (this is the same surgery that was intended to prolong Penny Hardaway's career, that Penny's recovery time was initially projected to be 4-6 weeks, that Amar'e was supposed to be ready by December/January after he had the surgery, which led to him injuring his other knee when the Suns doctors read the countless MRI's on Amar'e's knee and said he was healthy enough to play, pressuring him into the traditional mid-season 4-game return)... But the point is, there is legitimate uncertainty with regards to Amar'e's health that does not apply to Lebron James, Chris Bosh, Carmelo, etc.
But, let's say that, when it's all said and done, Amar'e ends up playing 3 years at his current physical level and then succumbs to further knee injuries. I don't know if this will actuallly happen, but I think it's a reasonable assumption, right? In that case, you'd be paying him max dollars in the 4th year of his contract, during which time he plays very few games and spends most of the season rehabbing from another surgery or two. And then, in his fifth and final season, he's a physical shell of his current self, looking like Chris Webber in his final season in the league. Some people might call that a "salary cap noose." I'd call it a $20 million expiring contract that half the league would love to trade for at the trade deadline. Unlike in years past, when a "max" contract meant 7-years guaranteed, now it's only 5 years. That cuts your event risk by nearly 30% (as compared to, for instance, Penny's 7-year deal back in 1999-2000). And, for goodness sake, Steve Nash and Grant Hill are making a combined $14 million this season!! The Suns don't have the financial resources to (potentially) overpay a superstar like Amar'e when two of their top 3 or 4 players make less than what it costs Nike to use Lebron James' name in a puppet commercial? Please!