The changes to Velocity are disappointing but they're a business and it's their right to do what they want. Status is a benefit of flying and my flying habits are reasonably consistent with a few changes as needed to maximise my earnings if I can retain/earn status. My primary programme is with QF. I'm LTG with them and had considered changing to another OW programme to aim for LTP, as QF's is way too high. Then COVID came and then my health issues, which will see me flying much less in the distant future, so that wasn't going to be feasible any more. Hence, I've stuck with QFF.
I travel to Europe at least twice a year and always in paid J on OW carriers, so that usually means I requalify for WP each year on QFF. Given that QF is often more expensive than VA domestically, I get work to pay for my work domestic flights and those flights then give me the requirements I need to ensure I retain WP with QF.
As for my travel habits with VA, I rarely credit international travel to VA unless it's on SQ to Asia. I don't fly UA, QR or EY. I fly VA domestically for leisure and occasionally for work. VA is cheaper than QF most of the time so it's better for me to fly VA when it's out of my pocket. I wouldn't go out of my way to chase status with VA the same way I would with QF. The current VA system let's me earn/retain WP with them reasonably easily. The new system will make it much harder to retain WP, so I foresee that I'll eventually drop to SG with them in the future. However, I will be very close to earning their LTG by then, so there will be even less incentive to fly with them once I reach that point.
In the future, I will be flying less, so my flying will primarily be directed to QF. Why chase VA when I now have to spend more and not get anywhere near as many benefits locally and worldwide compared to QF and OW? It feels like an "own goal" for VA and they'll lose out on my spend with them. I'm sure it's not a big deal for them in the big scheme of things but I think their bottom dollar will suffer when many people like me have to decide where to direct their spend (however much it might be) and, given the choice, the majority most likely will choose QF over VA. VA making it easier to earn status with them meant that lots of people could have a foot in both camps but if they force people to choose, they're likely the ones who will lose out.