Most successful icos now are without bounty. And it has increased this year. Project team.matters in successful ICO, the way the idea is pitched may also influence it. Very few good teams failed at ICO but idea still matters.
I believe these projects are not using bounties because they simply do not need it. A well funded ICO nowadays can spend near $4000 each day just on Google Ads. They spend 1 mil on Ads and get 20-30 mils on sales. That's how it works.