This is a manifestation of the decline of the market. It seems that ICO model has been difficult to finance enough money now, so these ICO-based bounty, the risk of not paying is also getting higher and higher.
It is not the manifestation of the market decline but rather the dropping quality of bounties and ICOs are caused by developers who want to get money real quick by proposing repetitive ideas/products on their ICO(which is typically not better than its competitors). This in turn results to ICO's failure.
It's hard to find a satisfying bounty /ico now,how long do you think the bounty can live?
Bounties will be there so long as people use ICOs to gather funds for projects here in cryptospace.