Not even close. As WT points out the main thing he would be giving up is the hypothetical 5th year. But the players have learned they would rather have opt outs after a couple years than the longer term deals so that's a moot points unless he gets injured. Let alone the fact that the players are very likely to opt out of this current crappy CBA in 2017. All the studs will want an opt out of their contract that year to sign bigger deals.
It's possible Wade will accept less than the other 3 since he's older and has some knee issues. Let's say Wade takes a Duncan deal around $10 million/year. If the total was $65 million for all 4 and Bosh, Lebron & Carmelo were equal they would start at $18.3 million each. The max Carmelo can make is $22.4 million so he would be giving up $4 mil/year over 3 years or around $12 million to be on the dream team. Very likely he could make that up in endorsements.