Both BTC and XMR have a relative and distinct value to what is perceived the dominant medium of exchange which makes it the UoA.
Change it for something else, gold, a CBDC, Bitcoin or Monero and you'll get to tally different relative valuations.
Everything is in flux.
(1) Normally we see fluctuations within the dominant MoE.
Meaning USD adoption gets bigger or smaller. Or there is more or less friction compared to its former self (AML), which then creates opportunity for competing MoE systems.
This is where BTC rose to prominence and where we compare Bitcoin vs USD (better protection against inflation, less acceptance) and Monero vs USD (better privacy, less acceptance)
(2) Then there are special times where the dominant MoE reached its end of lifecycle. In this scenario we can expect a nonlinear adjustment of valuations.
Meaning we get to choose a new dominant medium of exchange that ideally needs to check more boxes than the one before. In blockchain based systems we have the hard problem of scalability with self-custody and the soft problem of aceptance (that's only hindered on the social level through USD paid regulators).
Imagine a world where any of the following mediums becomes the new UoA.
1) Gold
2) CBDC
3) Bitcoin
4) Monero
How would you relatively value Bitcoin under a gold standard?
How would you value Monero under a CBDC standard?
How would you value Monero under a Bitcoin standard?
And how gold under a Monero standard?
Now take into account that there are some societal trends like digitalization. Some even converging like AI & government & surveillance.
How would any future dominant MoE fare under such a new regime? It might give you a hint what to look for from a perspective of power dynamics and degrees of freedom.