You have a question, so I will pretend to have an answer...
I'm curious what the movie industry is going to be like in 20 years. The medium is not going anywhere, especially since the technology to film is available to pretty much everyone with a cellphone, but can the same be said about the studios, especially if movie theaters were to go down? For now they are kept afloat by the parent companies, but how long do you keep a lame horse? I wonder how soon we're going to see a really competitive online distribution scene for independent productions (seems unavoidable) and if that changes anything in Hollywood.
I'd love to know what the movie industry would be like in 20 years, I'm sure the guys running the studios would like to know if they gave a rat's left butt about anything beyond their next bonus check.
Theatre owners would probably like to know, because feature films are the core of their business. They're what attracts the people who buy tickets, and more importantly, the snacks at the concession stand.
There are two ways theatres can weather this storm.
1. Bring back the glamour of the movie theatre. Back in the golden age first run movie theatres were veritable palaces of cinema. They were places people gathered to be entertained and to socialize with fellow moviegoers. That changed after the Canadians invented the multiplex theatre that turned moviegoing from a social event to an industrial event. Socialization was traded for getting people in, and getting them out, all as fast as possible, with each screening room have just enough seats to avoid having to provide wheelchair access.
People aren't going to go through all the hassle of going to a theatre to sit in an undersized seat in plain black box that is only interested in them paying for their ticket and getting the hell out as soon as possible. You're going to have to provide some glamour, some comfort, and some perks to get people going to the movies again.
After that the theatres are going to have to find something beyond what the studios are putting out. That means...
2. Alternative programming. Digital technology means that cinemas can do more than just show movies. Now they can "narrowcast" things like live concerts, plays, and other things people will be willing to pay money to see something they can't see at home.
That probably the two most glaringly obvious ways theatres can ensure their own survival.
Now the studios will survive the collapse of theatres because they're getting deeper and deeper into television, and online streaming through Netflix, Amazon and their own outlets.
As for the second part of your question about how long it will take for an effective form of online distribution for independent entertainment.
It's easy to get your movie released online. In fact, anyone can do it. But there are two pitfalls.
1. Getting people to pay attention to it. There are literally thousands of films of every variety available online. But how do you get people to know about your particular movie. You need money and marketing expertise, and they're not easy to get.
Let's not forget that the big studios can and will use their money and marketing expertise to effectively bury any and all potential competition.
2. Getting people to pay for it. There's literally an entire generation of kids who think art grows on trees and that the people who create it don't have bills to pay.
That means any online distribution would need the backing or support of some sort of large and powerful corporation like Amazon, Netflix, or a big media conglomerate to overcome those pitfalls.
I hope that answered your question.