One thing I have learnt in the past 6 months is that there is no need of participating in any ICO again if you can get is at 50% less than the ICO value.
Not every coin behaves the same. The price drops due to one and only one reason, is people trying to get out as soon as they get their token which happens because either these people are bounty seekers and they don't see value of a particular coin but just making some btc/eth and converting back to fiat which they can actually live with and those people who got some bonus like 30 percent , 20 percent and are happy with such confirmed gains.
When the companies stop these two things i.e paying out bounties or paying out bounties to only which brings in value and the bonuses to attract early investment. Pump and dump is still less affecting than this.