Helicopters are "stuck" because they've largely settled into an optimal configuration over the 70 years if experience designing helicopters. Some of the first helicopters had multiple rotors [1], but those were abandoned for good reasons They have a large main rotor because larger rotors provider greater efficiency. The single large rotor also provides the ability to perform autorotation in the event of power failure. Batteries are also bad choices for aircraft since they have very low energy density by unit of mass [2] combined with the fact they don't get lighter as energy is expended like thermochemical fuel.

These are the main reasons why quadro copters largely remain in the realm of drones and toys. These are the use cases where mechanical simplicity of four fixed pitch electric motors shine, and the shortcomings of reduced safety and lifting power aren't big issues (cameras weigh less than people and their families don't sue when they get smashed in a crash). You point out helicopters aerospace practices as a drawback, but in reality those practices emerged to deal with the responsibility and demands of human air transport. What is it going to cost to insure one if these flying cars? How many people's life insurance policies is going to cover rides in these things?

Definitely quadrocopters have made their mark in consumer electronics and even some commercial applications. But I am very dubious that people will be flying in electric multirotor craft.

1. https://en.m.wikipedia.org/wiki/Focke-Wulf_Fw_61

2. https://upload.wikimedia.org/wikipedia/commons/thumb/c/c6/En...