I'm gonna be honest, sometimes I feel insecure about using old voicebanks because everyone seems to be moving on to the fancy cutting-edge AI technology and I'm still using concatenative voicebanks from the V3-V4 era (with the exception of maybe Chis-A, who's free anyway). Yes, I can use SynthV Basic, but since that's NG for commercial use I feel like I can't use it to make original songs lest I eventually sell them.
Then again, my idealistic 12-year-old self specifically wanted to be a Vocaloid producer, and the things I experimented with before purchasing Miku, such as UTAU, Sharpkey/Deepvocal, and the free versions of SynthV (R1 evaluation and R2 Basic), and even RenoidPlayer and Sinsy before I even had access to anything more than a Chromebook (I had a PC I could use since before Web SynthV came out), were just to get me ready. Part of me just wants to honor my tween-age wishes, and I'm also super used to Piapro Studio by now.
But at the same time, in both the vocalsynth fandom and music-production communities, people are largely leaving the old stuff behind in favor of AI-powered stuff, especially SynthV at least in the West. Many of my favorite vocalists are getting updates- and for those who likely aren't, fans are screaming for them to, acting like their companies are criminals for not giving them such- and some new vocals are super tempting too, especially if I could potentially use them well in my favorite genres. But I can't afford it right now, and even when I'm set up with a job I can't just go spending all over the place no matter how much people say "you should totally get X Y and Z!"
Add to this the fact it's the same genres that tend to take the lead because they're the most spammed and you get users wanting desperately to get noticed so they go the extra mile to appeal instead of doing what they really want to do at core (except for those who love said genres, then it doesn't revolve around them since they're already in their elements so it isn't the same approach)
Also while I won't deny I've kinda overdid it lately for the past one year and a half, it still kinda makes me ill-at-ease to see loads of sales even though it's way better than in the past since it permits people to buy their synths without sacrifying their monthly wage or wait for billion of years to be able to buy the synth they want.... But yeah, while some like me can hold back and say "well, too bad for X/Y/Z I will buy them when i can have a better situation since it's gonna be too tough for the on-going period" as I've been doing since my last purchase back in late February because of life, but other people may ruin themselves, and I've noticed some were even younger (some are barely out of minor age) splurge loads of money at a bigger frequence than i've been doing in my massive buying short period and yeah, as you said people do whatever they want with their earnings and savings, but everyone should keep in my mind what they buy can be considered as a sort of luxury item like a jewel or very fine-end delicacy