It used to be consistent for years post-9/11. Rules were enforced more or less consistently. Especially the liquids rules. Some variations but not to the degree that it is at today. This chaos is only the past few years.

Strongly suspect it has nothing to do with security and everything to do with the system breaking down due to abysmal leadership.

Also probably the paid extortion programs like CLEAR which have separate relaxed rules standards for people who pay the extortion fee.