The problem with "blowing it up" is that the team would need to move the contracts that are hamstringing them AND be bad enough to pick at the top of the draft. The former is almost impossible, and the latter is actually harder than it sounds. Who is going to take on Jackson's contract, even for nothing in return? What other team in the league would pay Drummond max money? Blake was literally being shopped for months, and the Pistons were the only team willing to give back anything useful in exchange.
But more, even if we gutted the roster we don't know if it would get high draft picks. The change to the draft lottery means even the worst team can pick as low as 5th (which is not far off from some of our latest picks). There are still a handful of teams currently dedicated to tanking (Cleveland, Chicago, and Atlanta).
I personally think this team needs to be blown up, that the front office needs to take a steady and long-term approach to rebuilding. But, I don't think that's possible right now. I think our best plan right now is to build in the margins (minor upgrade at the 2 spot, hunt for a salary dump PG). Don't take on any big contracts that run past the 20-21 season. At that point, let Drummond walk and any other vets making more than the MLE. If Blake is still good, dump him to a team looking for vet leadership (most teams will be able to handle an expiring contract). If he's not, force feed him the ball and let the team fall apart around him. Start over with a clean slate and focus on the draft.
That's not ideal, as it's still 2 years away, but it's probably realistic. This is the team the front office has built, and they are stuck with it.