[ranman]

"Nothing practical to show" ... I think you may be misinformed. There are a great deal of practical advancements (raptor engine, carbon fiber tanks, software and sensor suites that enable autonomous landing). There's tons of room for discussion around the mars architecture but to discount it because there's "nothing practical to show" is incorrect.

If you're not an expert in the field it might be worth it to do some research before immediately discounting an idea.