Just because they are supporting it, doesn't mean it's in high usage yet. Again, it isn't.
DLSS is application dependent.
RT is application dependent.
Both are in very few games at present.
The fact that you seem to NEED DLSS to even play with RT at even some basic level speaks volumes about why most people shouldn't be bothering with it. Should companies keep pushing for it? Yes, absolutely. But that doesn't mean it's at a level for most people yet.
Let's be honest here. How many people are actually buying the 700/800 GBP/USD cards cards? The vast majority are on older generations or will be on 3xxx/6xxx series cards that just aren't capable of decent levels of RT. Most people are NOT using 4K screens.
DLSS is a band-aid to a lack of performance, but it's marketed as a 'performance enhancer' when it isn't. It allows you to get 'close' to higher resolutions in a few titles, whilst sacrificing visual fidelity, that your card isn't capable of natively. In short, it's there to make RT useable and for marketing purposes.