Past results have 0 predictive value for future results; I'm pretty sure most front offices know that and I'm positive that you do.
Of course. That doesn't change my point that even under the current odds, the worst team has a 75% chance of not winning the lottery, yet we still see teams tanking. A better chance is a better chance and a positive, non-zero percent chance is better than a zero percent chance.
You're ignoring that tanking isn't about "winning' the number one pick, its about getting the highest pick possible. If you have the worst record you can't go lower than 4, second worst 5, etc.
This makes the calculus of 75% not to win the top pick deceptive, teams are looking at getting the highest expected value for their pick. A team that backs out of the playoffs has a very high upside if they jump up, but their risk is massive as by far the most likely outcome is that they stay at the 14th pick (or whatever they slot to).
This sort of massive risk isn't something teams are going to be willing to do for a 2% chance compared to playoff revenue and the other benefits of the playoffs. Plus the risk of driving away fans by dropping out of the playoffs.
An estimate of the increased expected slot of dropping out of the playoffs for the new proposal would be as follows if they had a 2% shot of moving into any slot 1-6, assuming they get the 14th if they don't jump: Note I simplify the math a bit so my calcs are a bit off a full value tree
89% of not jumping stay at 14
(1+2+3+4+5+6)*.02 + .89 * 14 = 12.88
15th pick plus playoffs
They'd be missing the playoffs for an expected jump of about a slot and a half (because my simplifications slightly underestimate the odds of jumping up) in the draft on average. That's a terrible return considering the lost revenue and the backlash.