Lots of ppl will ofc stick with their z690 builds, I don't disagree. Many building new systems will want a DDR5 platform supporting years of upgrades and for some, the new I/O options will be important too. A lot depends on DDR5 pricing too, AMD is supposed to be working on trying to bring prices down, who knows if that will be successful, might take a little longer than they would like.B650 prices are set to be much more than their AM4 counterparts, plus doesn't negate the need for expensive DDR5. As I mentioned in the post you quoted - just can't see how this will compete with 13th gen i5, z690 board and cheapo ddr4 in price/performance.
I think AMD would be mad not to try to incentivise the production of at least some cheap B650 boards.