The Starship program so far has soaked up as much money as SLS, and hasn't even left orbit.
Full-flow staged combustion metholox engines.
Stainless steel construction.
Biggest rocket to have ever flown.
Highest thrust at launch of any rocket by a factor of two or so.
Live streaming of reentry via a space Internet network.
Etc…
Quantity has a quality all of its own.
You should be familiar with this from IT: there’s nothing fundamentally different about the first computer that I’ve ever used to the one I have right now, other than the factor of a million difference in performance!
Why not? With the capability demonstrated today, they can just as easily tweak the ascent profile to end up in a stable orbit outside the atmosphere. Their trajectory was suborbital on this flight on purpose.
There's a bit of nuance to what you are claiming here.
SLS cost $11B to develop, which is estimated to be in the neighborhood of what Starship will cost when development is complete. We don't know how much has been spent so far.
A huge difference is that producing and launching an SLS rocket costs over $2B, while SpaceX is estimating $10M for Starship. Now, I don't trust that $10M number, that's what they aspire for it to cost. To do it they need to be able to reuse the stages dozens of times. It could take a long time to achieve that or they might not make it at all. However, $2B+ per launch is a whole 'nother level of expense.