Umm, I bought a no-name (but Gillette-compatible!) razor last week while travelling due to having left my usual kit at home.
Having used the no-name one for a week, I can no longer see any reason to pay the extra for a razor brand ever again.
Granted, I haven't looked at prices in a long time. I am mostly assuming not insane costs.
I'm not sure what "insane" would mean in this contect, but replacement blades for the no-name Gillette clone I bought are half the price of original Gillette ones.
My week using the former showed that, for me at least, the performance of the latter really doesn't justify its price. YMMV.
It's likely that even small companies are selling enough that these costs amortise to near zero.
I also cannot tell the difference between that and just buying safety razor blades, though there is a huge advantage (for me) in the pivoting head.
Also, the article links to a study which found DTC to be 10% more expensive than traditional retail.