I don't think that we'll get to another planet in my lifetime. It's not just the extreme cost, but also the risk. As the aero programs have matured, the tolerance for risk has gone down dramatically, and if there is a single (or god forbid multiple) high profile deaths caused by the pursuit of trying to reach another planet, it will stall the program for a solid ~10 years. Eliminating the chance for risk slows down the effectiveness of the program. I've only got about ~50 years left being modest, so I doubt that we'll get to another planet in my lifetime.
Perhaps another country will be less risk averse, but it's difficult to justify. India has made remarkable strides on a shoe-string budget over the last 10 years, but those strides simply wouldn't be possible if it weren't for the work done by countries with massive space budgets in the last 70 years. The US has a reasonable aversion to the cost of the space program, but countries like India and China -- very capable of continuing development of their programs -- should have an even greater aversion to those costs. When the job you are hired for is to protect your citizens and provide a happy, stable life, it is difficult to justify spending $100b on space program, when $100m could go to preventing hunger and disease (very real problems in the developing world).
For a country like the US, or any European country, somebody could say "Why not both?" But, for a country like India, it's a tougher sell. Nevertheless, the strides that India has made on that very small budget over the last 10, 20 years, has been great for the space community in general.
I don't believe so. What's the phrase, "it's not the destination, it's the journey?" The scientific discovery that the journey would require would be most beneficial and would certainly have tangible benefits for us here at home. The destination, not so much. Either way, I don't think myopic political leaders would ever want to pay* for that journey.
*with fiat currency we can create from thin air, meaning it practically costs us nothing other than slight inflationary pressure.
I'm just going to assume you know more about space travel than you do economics. Or do you think that dogecoin will get us to the moon?