From its very beginning, the space program has been a tug of war between those that see it as man’s destiny to explore and those that see better uses for taxpayer money spent anywhere else. The main reason for the Apollo program’s success was that there was a national concensus that we needed to face down the Soviet Union for superiority in space. JFK’s commitment to reach the moon by 1970 caught NASA by surprise, but he had the support of the majority of Americans who were willing to pay the price. The Soviet Union no longer exists, and we no longer fear Russian dominance, so that motivation has gone away. But, as Paul points out, we should be concerned with the Chinese, who are clearly pursing dominance in space as a national priority. Whether it’s for peaceful purposes or not is anybody’s guess, but I would prefer to not find out when it’s too late.
As for the cost, NASA is run by the government, which means it has to use subcontractors scattered across the congressional districts of influential politicians - arguably the worst way to fund anything. SpaceX has the advantage of an efficient supply chain and the ability to make changes on the fly by blowing up their mistakes to learn what works best. With their budget constraints, NASA has to be very careful to not make any mistakes because they can’t afford to blow up a single SLS. As for me, count me in on the “Go for TLI” side.