Many of the modern claw machines are computer controlled for payouts, sadly.
They're set to have "weak" grabs for X number of times then a decent grab every so often, to ensure the machine operator makes good profit. They still require "skill"; even if you get a good grab, poor aim will prevent you from scoring a prize, but more often than not the game is set up so you won't win on skill alone. I never play those machines because of it.