The greatest problem with space exploration is that most people don’t talk about it or care as it doesn’t directly affect them therefore there is no hype or excitement to do it. Even if people understood all the benefits there is still unlikely to be much interest simply because it needs to be accompanied by enthusiasm and hype. If a load of celebrities started taking an interest it would probably become more popular but sadly people would rather talk about celebrity gossip than talk about a mission to Mars or the future of humanity.
Ultimately there are only 2 ways for a Mars to Stay mission to become a reality:
1- There is a fundamental shift in people's opinion and attitude towards space exploration to the extent that there is a clear demand for a mission to Mars, enough for politicians to see it as a popular policy and even for businesses to sponsor.
2- A high ranking politician or an extremely wealthy individual is passionate about it themselves and wants to see it get done. In which case they have the influence/finances to lobby other people in similar positions and would see that either a government and/or private mission was put in place. The only individuals that fit this criteria right now is Elon Musk and to a much lesser extent Jeff Bezos.