Why Do Musicians Still Need Record Companies?

I know some who are long-term weed smokers and like all pot-heads suffer from the delusion that their mental acuity
has not suffered.

The OP asked about record companies, not managers or agents. The admin and financial work mentioned in several responses usually falls to a band's manager. As many have noted, it's usually a bad idea for a band to self manage. See Fleetwood Mac's disastrous experience with Mick Fleetwood at the helm.

Either way, the record company plays a different role.

Leonard Cohen had once manager too, but realized too late that this biatsch completely destroyed his wealth and I doubt that he's ever had any closer than friends relationship with har(the biatcsh).

The 18mts sentence for har was a joke and help from 'Nicky Santuro' or similar movie character doodz found in reality would be much more fair and efficient(in terms of funds recovery) than Court of Law. https://www.youtube.com/watch?v=3ZzAS53gcDg

That huge depletion of his wealth indeed triggered his latest large tour and 2 new albums. Ain't no bad without good tho and I wish his way to be as long and strong as it possibly can be. I wish him outlive Les Paul and make more public apearance, great albums and great books.

Nicky gets the job done well!

Raise money to pay for the recording. Hook up with a sympathetic producer. Eat and have a roof over head during recording. Promote record release. Distribute recording to industry influentials and actually get them to listen. Book tour dates. Arrange travel and lodging. Promote record on AM talk shows/promote record on late night talk shows. Tour. Get song on movie soundtrack. Appear as guest artist on another artist's album. Equipment van stolen, replace all instruments. Become the opening act for mega-star's Australian tour. Get replacement drummer (passport problems). Live the dream for three weeks. Get back home and continue touring, but now you realize how crappy your tour bus really is. Feel good as you hear one of your songs over the radio at a convenience store. Finish tour and have accountant tell you you're $65,000 in debt. Start writing songs for next album...