Probably it was just being dumped. I am speculating that team managing the project were now in working in different project for if not then they should considet promoting it and began marketing it to more users in crypto market by listing it in different exchanges. Binance.is one good exchange to be consider if the project has the money to spend for it for listing fee in BINANCE exchange.
Yes, these old project If they are really good can still be promoting their projects since they still have supply left to be sold, so they should be more active in making it work better rather than just waiting for bull run, some of them actually picked up in the last bull run if you check their data history, so instead on relying on their product to work and earn them a good value, they keep relying on Bitcoin bull run to do the work for them, but like you said, they might actually be working on another project too which might have even been released without us knowing.