Re: Methane?
There was and is absolutely nothing wrong with the concept of the Big Dumb Booster.
They are a straightforward engineering way to get *LOTS* of mass into space in a useful way in ONE GO. Often relatively cheaply. O2/H2 plumbing is seldom simple and never cheap.
The Sea Dragon conceptualized in 1962 could have been built with then current technology and gotten a huge amount of useful stuff into orbit. Sometimes bending LOTS of tin quickly to get your job done is not considered bad.
The reusability case that Elon Musk brought to fruition was *ALWAYS* the goal of a true space-faring society but actually getting stuff into space is pretty much the only goal we measure by.
There are still use cases for expendables now. IF they are cheap and/or plentiful and can actually do the job you need done *now*. Re: Rocket Lab Electron
Launch often. Break things. Iterate. Improve.
Per Aspera Ad Astra.