So i want to put a small disclaimer here !!! Before i start. I was a backer long before i became sort of a member with a tag with my name that gives me (SLG Admin) but i wanted to comment you what made me decide to back eco back in the days since you concern is pretty valid and people should always think about before backing. So this reply will be my personal opinion i had back then and not an official reply from SLG. Just to point this out =)
You are right with your first point! Lots of kickstarter projects get abandoned and some are eve there just to cheat people out of there money. That is sadly though one of the risk people have to take when backing projects there from small and unknown companies. Though there are some thinks people can do to have a higher chance to back project that will see it trough to the end. So let me make an example:
I did some research back in the days when i originally was backing Eco. First of all is what games have been commercially released. At first look there are not that many for SLG yet But there is one game Called Vessel that even got very good reviews even though it got pretty few of these. You also have some other smaller projects. But for now Vessel is a very good example of the skills of SLG. This also tells you that SLG is at first glance not a company that starts a game and never delivers. It really helps if a company has delivered at least one game that is good personally for me. Next question would be founding. We all know that most devs ask to little on kickstarter. Eco's initial KS goal was 100.000$ well that would give not allot of month of development time actually. KS got around 200.000$ in that would maybe cover 6 month of cost? maybe more ? I dont know how much it cost to run a company in a month but i am pretty sure that this cant be cheap. You have office cost, developers want to get payed and not minimum wage but a good payment too ( you need skilled people especially in small teams). So that seems to be to little right ? So what made me confident back then ? well its this article here that i read http://www.eurogamer.net/articles/2015-06-09-introducing-eco-an-ecosystem-sim-where-everyone-must-nurture-the-same-planet. This has allot of talk about eco in school but also has a link to that eco got funding from the us government with a quite large amount.
So pointing this out This also answers sort of your second question. This means you also have a rough estimate when eco should be done. That is somewhere in the second half of 2017. Now Estimating a release date is always impossible and dead lines are rarely kept since there is always something delaying a development. Anyway this means and also with our current official goal the 1.0 release should be around by the end of 2017. The plan is to keep on developing as long as its financial viable and keep on expanding eco (a bit like other games did ) Because there are so many more cool ideas that could have been added to eco but most likely wont make it into the final release at first.
So i hope that gives you some insight why i backed eco back then and what made me decide to back it.