Some Mixers support the BTC > XMR > BTC feature to enhance anonymity thanks to Monero. Users of these services want to own BTC, not XMR, because BTC has more potential than a privacy coin, as evidenced by the long-term downward trend of the XMRBTC chart.
Do not mess up mixing coins and trading. Users who use the mixer certainly do not do it to make some trading profit, because these are two completely different functions. Surely no one decides to hold XMR or any coin just because they can convert BTC to XMR through a specific mixer.
If you are already talking about the drop in the value of XMR, there are serious reasons for that, delisting from some large exchanges plus a serious fight with the SEC certainly have a big impact on everything.
It is in the interest of the entire crypto ecosystem that XMR survives everything that happens against it.