Totally agree with you. Bounty is a good way to attract extra attention for the project, but there should be fresh news, announcements about partnerships etc. to make people interested in the project.
Of course, investors won't be interested just because someone put an ICO ads in someone's signature. they are interested because of the innovations they bring, bounties will not be enough to attract and make people interested, the actual function of the bounty is so that people know about the existence of that project, for interest depending on what the project brings