> 1. bigger and much more capable interplanetary probes
The limitation there is capable RTGs, not launch vehicles.
> 2. a much cheaper Webb telescope
Webb couldn't have fit into a Starship fairing either.
> 3. build a base on the moon
For whom? Launching stuff is one thing, but you'd need to design, build, maintain, and supply such station. If you think the ISS was expensive, a Moon base would dwarf the ISS costs. Even if launches would be cheaper, there's still a lot of logistics and support behind such station, which is one of the reasons no one did it yet.
> 4. make a mission to Mars possible
That could be done without Starship - as much as I think Zubrin has drifted into the nut job corner over the past decade, he still has a point: crewed Mars missions would've been possible since the 1980s.
You know what costs even less? Building a larger fairing.
Atlas V has different fairing sizes for different payload types as well.
Sure, a bigger fairing will simplify a space telescope, but you still need to fold it and the bulk of the costs went into developing instruments and the mirror.
There's nothing "simple" about a state-of-the-art scientific instrument. If you want Hubble 2.0, NASA has two of them just lying around for over a decade now; gifted to them by the NRO.
You know how much converting them to useful scientific instruments costs? According to the latest report, it's about $3.2 billion so please give me a break with your "simpler and cheaper because fairing".
> because it turned out smaller planes are more economical
Per seat the A380 is still the cheapest way of moving a person by air. The 777X should beat it, but it's not in service yet.
The problems with the A380 were (1) it wasn't aerodynamically radical enough to maintain that advantage beyond one generation of airliners and (2) you need to fill it to compensate for (1)
The limitation there is capable RTGs, not launch vehicles.
> 2. a much cheaper Webb telescope
Webb couldn't have fit into a Starship fairing either.
> 3. build a base on the moon
For whom? Launching stuff is one thing, but you'd need to design, build, maintain, and supply such station. If you think the ISS was expensive, a Moon base would dwarf the ISS costs. Even if launches would be cheaper, there's still a lot of logistics and support behind such station, which is one of the reasons no one did it yet.
> 4. make a mission to Mars possible
That could be done without Starship - as much as I think Zubrin has drifted into the nut job corner over the past decade, he still has a point: crewed Mars missions would've been possible since the 1980s.