The X-33 & VentureStar where an atempt to do that, and NASA screwed up.
The real issue is that back in 1972 Apollo colossal infrastructures become entrenched in Congress as a job-program; and as such, had to be recycled at any cost into the Shuttle.
In a sense, this delayed the problem by 40 years until 2012, when it came bitting once again.
"Apollo built it, Shuttle used it for 40 years, now what ? retirement ? no way. SLS ! Back to Saturn V !" Except without an Apollo committment behind it.
We have a few expensive Saturn V (the three SLS flight planned so far); a few expensive Apollos (Orions) - and nothing else, at least not an appropriate budget.
NASA has made one smart move to try and get itself out of that SLS mess in the future: picking Starship for the cargo lunar lander program. Despite of course the big risks related to it (massive orbital methalox refueling).
In a sense, NASA
- hired Starship for the lunar cargo role, and as a possible "Plan B" to SLS-Orion if unsustainable or canned in the future
- this way they encourage / support Musk Mars plans - through their own lunar program as started by President Trump.
Basically: Musk is not interested in the Moon
- So there is some room for NASA use of Starship there
- Which is quite welcome as a "plan B" to the expensive and troubled SLS-Orion "plan A".
That's only MHO, of course.
