The thing is tanking doesn't always work.
The Sixers sucked for a season, then ended up drafting #6 in 2013 and took Nerlens Noel.
They sucked again for the next season and ended up drafting #3 in 2014, taking Joel Embiid.
They sucked exotic wang for the next season and ended up drafting #3 in 2015, taking Jahlil Okafor.
Then they sucked some more, ended up drafting #1 in 2016 and took Ben Simmons.
Then once more did they suck in order to trade up to #1 this year and draft Markelle Fultz.
That's 5 years of full-on tanking, to draft 2 or 3 guys who are solid impact players.
In other words, the hit rate even at the top of the lottery is around 50% or 60%. You have to take multiple swings at it.
That said, there are good players available in the middle of the draft. You just have to be daring enough to draft them.