It is up to the manufacturer to implement it, most esp devices like 8266 and 32 have weak security firmware, are easily hackable (benefit to me). Most don't have security in mind and don't get security updates.
If someone wants to get a hot air station and a bunch of $1 chips and reprogram their own devices, it would cost them less than a hundred dollars, 150 tops.
Anyone can learn any skill. If you can draw anything recognizable, you can do electronics.
From AliExpress, it'd probably be $2-$3 including shipping.
They don't ask questions when ordering large volumes of microcontrollers either.