On what basis the people buy the new ICOs and Tokens?

[IGCGamers]

I see a lot of ICOs are coming every day with erc 20 tokens. I also see lot of people are showing interest on that. On what basis people show interest on the erc20 tokens? Do they really think that the value of the token will increase in future?  This might be okay until 2016. But after 2017 lots of tokens are coming up every day. So, there won't be demand in the product. Without demand how the value of the token/coin will increase? On what thinking people invest on the icos and new tokens?

Please share your views