No he couldn't have done that...mostly b/c most of the guys you mention were essentially untradeable before the 2010 offseason.
Randolph costs less because he isn't as good. I'm not saying Randolph is bad - but the fact is Randolph isn't a gamechanger to the extent Amare is. Do you think that this team would have done as well if you replace Amare with ZBo early in the year, when STAT carried this entire team on his back? Hell, would Carmelo have demanded to come here to play with ZBo?
That's not true. Walsh got rid of Quentin Richardson, Jerome James and Jared Jeffries before the 2010 offseason. That's 25 million dollars off the books.
It's not all about getting big names. It's about building chemistry between players.
Zach Randolph, Wilson Chandler, and Jamal Crawford had experience on the Knicks. They knew what was expected of them.
Passing up on Brook Lopez, Roy Hibbert, and Brandon Jennings is inexcusable.
The Knicks could have still signed another Max contract, had they kept Randolph. All they had to do was dump Quentin Richardson, Jerome James, and Jared Jeffries which they were able to do shortly after dumping Randolph for crumbs.
Being that Walsh was able to dump Quentin Richardson, Jerome James, and Jared Jeffries PRIOR to 2010, that shows Walsh just needed to be patient and the Knicks could have had a good core of players who had experience playing together, instead of having to start from scratch like how they're doing now.
I like Stoudemire, Anthony, and Billups, but this team is built with guys who barely know each other and are going to have to spend AT LEAST another 2 years together before they can legitimately be contenders. And that is a big if, considering Stoudemire has bad knees and might not even make it that long.