Why is the government formed around a representative people party and not around a problems/improvements priority system?

Why isn't there a government system that uses the majority voting system against problems/ideas that need to be addressed within a society, e.g. having referendums on every vote. The point of this is to eliminate the need to vote for a political party and a person (president/representative) that advertise an agenda of what they think needs fixing and what they propose to do, because this has high chances of corruption, manipulation, false promises, bribery, etc.