I love Whirlpool, but it's like ~6,500 BTC total capacity last time I checked. $150,000,000 in Whirlpool VS $2,700,000,000 in Monero.

Even if you add in Join Market, Wasabi, and whatever other privacy remnants into the equation, the anon pool is still much smaller than Monero.

Monero also uses signer decoys from the entire past of it's blockchain iirc.