I believe it is due to both things - some projects are indeed amazing, however, their value is overestimated which leads to rapid boost in price, which is beyond normal. Additionally, some do it out of greed because the core idea of ICO's are to raise funds for the companies that launch them. However, there are many ongoing and upcoming valuable projects that are either non expensive, or their value is worth it. Such are, for example, Cointed, Giftz, AgroTechFarm, and Beat Token. All of them hold a lot of potential, at least in my opinion. Check them out, in case you are curious.
Agreed. I think most ICOs are way too greedy and try to raise more than needed (and succeed in raising the money in a lot of cases). The ones you mentioned (Cointed, Giftz, AgroTechFarm and bee token) are exceptions, the few legit ones in a sea of greedy ICOs