Base on google, this is their reasons.
LocalBitcoins, one of the oldest and best-known Bitcoin exchanges, is closing after a decade of service, with the peer-to-peer platform citing the “ongoing very cold crypto-winter” as the reason for stopping operations.
But I don't think it's the reason because they exist since 2012 when Bitcoin price was below $1K and there was a dump in 2018, yet they were not shutdown at that time.
They were known as No KYC P2P, since they implement KYC mandatory rule
on 2019, it's where they lost their customers.