Caporegime
This is where motherboard prices will be really important.If the 3800x is level with a 9900k in games using just xfr I'd still say that's a success and will sell well given it will be cheaper, run cooler, have pcie4 compatibility and a possible upgrade path to a refresh. Even if the 3800x is only fractionally cheaper taking the board into account, it's hard to justify the 9900k now. Then again, it's been out a while so is that really a surprise.
For people planning a total system upgrade, Intel wouldn't have to drop the price of the 9900k by an awful lot to turn my head, as the motherboards are (presumably) cheaper than the X570s will be on release.
For example if I'm left with a £480 9900k vs. a £400 3800X but can get a top spec 9900k motherboard for £100 less than equivalent X570 (given I have no use for PCIE4), I'd have to think twice about Zen2.
Obviously that doesn't account for upgrade paths.