There is nothing that can be done if investors decided to dump the coin and the price keeps falling. The only up option here is to buy back the token which could make the price stable but may take a long time for the price to recover from the bear trend. This has happened to many devs in the crypto market and what they could do is to buy back the dumped token so that the price can start going bull investors comes back to the project and buy them.
Marketing is one of the ways we can increase the numbers if investors of a token and keep the price going bull as more investors comes in to buy it.
Yes, you are right there, and then it probably also depends on the token to see if it really has the potential to provide good benefits to those who will hold it. If there are market innovations that are called for sure, the previous communities in the field of crypto space will not let go.
But if they don't really see development and innovation, the communities will probably leave it little by little. If there are no marketing plans for the future, the price value of that token will really fall. We should observe what other token projects are doing in their marketing scheme development; others who just copy and revise a little will be fine right away.
The problem with development and innovation making it go higher would be that if it's too late then it may not help. If you constantly have a new thing every month then yeah that's great and should keep you high, unless something bad happens of course.
However, if you make nothing for a year, and then do something great, most people are already gone and the token price crashed and that's the issue, I do not think that it will get anywhere outside of that, we should probably just consider that as a problem. I think it's quite foolish to have this kind of thing, it would make a lot more sense if we knew what we were doing and not really have any big issues, because in the end, we are talking about a deal where it is not that simple if devs are not around.