IEO projects on P2PB2B are because they do not have enough funding and do not have the professionalism to get IEO on large exchanges. Large exchanges only support really potential projects and the dev team must have enough talent to develop the best project possible. That's why shit projects often go to P2PB2B or Yobit to get token sale.
there are ieo's on big exhanges afaik . ieo must be listed on better or bigger exchanges so that they can get trust easily to thier investors but if an ieo will only be listed on poorer exchanges , that will only cause doubts for the people that are going to invest with it .
but you might be right . maybe they dont have enough budget because i think listing on good and large exchange is not easy and might require some costy fee but if they wnt the best out thier ieo why not sacrifice some funds eh ?