In general, this is true - the longer ICO lasts, the less earnings for members of the generosity campaign. However, this is not applicable to all cases and not to all ranks. The higher the rank of the participant in the ICO signature campaign, the greater will be his earnings gap as the duration of the ICO increases. Also, sometimes a long-term ICO brings more profit than a few short ones. Everything depends on the specific ICO project and its prospects. Therefore, it is impossible to determine in advance how long the ICO project will turn out to be successful.
Yes, it is forgotten that the member's ranking plays an important role and if there aren't a low of higher ranks, those at the highest will benefit the greatest, regardless of how long the campaign is