Or he will create an account, make friends with members, earn merit point, make a position in the DT system. Will establish himself as a dedicated forum member. Then suddenly he will start asking for loans. He will start from small amounts. Slowly he will increase the stake. Once it will be enough to run away, he will simply scam. Haven't we seen it many times?
This isn't as easy as you say it and it takes a very long time to earn the status of an "established" user on bitcointalk or to achieve some of the things you mentioned. I get it that we have seen a lot of loan defaulters in the forum, but lenders have also learnt from it; and someone who comes into the forum with the intention of doing things like this would prolly never succeed.