If they add a couple decent free agents around Lopez and Young, the Nets can compete for a playoff spot for the next couple years. Without their own picks, they gain nothing by blowing it up. The minimum team salary is going to be around 70 mil next season and the following season it will be around 90 mil. So whoever they have on their roster, they are going to have to pay them a lot.
A few things:
Firstly, I think it's debateae how much the Nets could compete for a playoff spot next year with a couple of quality, but not star, free agents. They've been healthy so far (minus the recent RHJ injury). Their record is very indicative of who they are, if not overselling it slightly (their point differential is worse than their bad record indicdtes). They're about where the Knicks were last year. The Knicks added some quality free agents in Robin Lopez and Aaron Afflalo, plus a potential rookie of the year in Kristaps Porzinigis. Carmelo is also back healthy. And that has propelled them to 12th in the conference more than a quarter way in. Adding 2, or even 3, such players is likely to result in nothing better than what the Knicks have done.
Secondly, suppose they add 2 decent free agents, on 2-year contracts because they're trying to not get bogged down long term. Where will they be in 2018? Those free agents will be gone, Lopez will be 30 and looking for another new deal. They'll have a year left or RHJ's rookie deal, and whatever 1st they get from a swap. So now they get to play free agency roulette again, and if it doesn't land on their number, then what? They'll be farther away from competing than they are today, because they will either have to pay Lopez or let him walk and get nothing. Same for their other free agents.
On the other hand, suppose they trade Looez, Young, and get a first and a few seconds. Then suppose next summer they take on some unwanted contracts in exchange for more assets. Perhaps they get Kevon Looney for taking on Andrew Bogut so Golden State can pay both Barnes and Ezeli. Perhaps Houston thinks they can make a run on Durant, so they dump Brewer and McDnaiels, and a 2017 pick. Those are just some examples. But anyway, now when 2018 rolls around they're the same boat financially as they would doing nothing, except they have more picks. Furthermore, they can play acquired guys like Bogit, hopefully causing a better record.