In article ,
says...

Because NASA isn't getting enough money!

Bull$****! NASA is being forced to spend money in stupid ways due to
politics. SLS/Orion are the poster child for wasteful government
spending designed to spread spending throughout as many key districts as
possible.

Bigger and bigger launch vehicles aren't the answer to everything. In
particular, developing technologies like inflatable reentry shields is
one of many enabling technologies that helps to eliminate the "need" for
very large launch vehicles for a manned Mars mission. Cryogenic storage
of LH2, LOX, and other cryogenic propellants is another. In space
refueling of cryogenics is yet another. In situ fuel production...

The list is seemingly endless, but each piece, if taken as a small R&D
program, wouldn't be terribly expensive compared to the seemingly
"obvious" alternative of the uber expensive SLS.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer