It was never a good idea. Labor already has far too much power and has since the Federal railway legislation.
The ESOP was never implemented right either, sinc employee-owners had no right to sell their stock. It was always viewed as nothing more than a way for the pilots et al. to increase their own compensation at the expense of everything else including other shareholders.
Worse yet, it created competition by other airlines' work force for ever higher compensation that would match or exceed United's.
The result has a lot of connection with the current airline crisis. Essentially we had labor unions dictating airline economics and the results show.
Airlines like AirTran or Southwest that somehow avoided the "matching" that went on with AA, DL, CO etc., are making money. America West is close to making money. Labor unions do not run those airlines.