Lets face it, Youtube won't last forever, at least in the sense that people can play games, upload video and make ad revenue.

It could very easily last multiple lifetimes, and if not youtube, something else will absolutely pop up. Making money on the internet for making videos is now a thing and it's not going anywhere. Where do you get this idea from? The only possible way that it stops is if a new medium comes out and people stop making videos and start making well, whatever that new thing is that I can't comprehend. Maybe crazy VR stuff, who knows, but it will always be something.

As for age I think that gaming online is coming to the point where we are going to see older and older people doing LPs, playing eSports, and much more. The age that limits pro sports players isn't even an age that we're hitting online with games yet, and I don't think what so ever there is that hard limit with games.

Everyone who started doing this 5-10 years ago and is doing it still isn't going to magically go away, they will continue doing it for a while. Maybe they find new projects, grow their channel into more than LPs only, and maybe they even create a small community and market around themselves that they are part of, profit from, but aren't the main entertainment of. Look at something like say, Linus Tech Tips, where they have multiple channels now with all of these workers. He literally owns a company that does all of these things. Similarly communities (more comparable to the topic here) like Yogscas and Gamegrumps also have multiple channels, many people involved, basically entire businesses created around this concept.

Streaming for instance is JUST becoming what Youtube was, and we already have people making 100s of thousands of dollars. The first million dollar a year streamer probably doesn't even exist yet. With eSports growing, I assume this will become a thing, and youtube, twitch, and all of the other little companies trying to get their little slice will all be places people go to produce this content.

I think everyone trying to do youtube needs to have other plans sure, I mean even if you're making let's say, 50k a year, that might run out someday, or you might want to move on or move up, but you can't just get a promotion. You will need to either be saving a whole lot of that money over the time you make it, or you need to have other options. I personally think anyone doing youtube full time should also be getting schooling done. Get a degree, find something you know you can do, try and connect it with youtube if you can. Some of the big guys on youtube have media friendly degrees these days, and many of them now work for/own or are part of companies that deal with media.

Now I'm obviously talking more about those who aren't doing much else, but you should remember that most people doing LPs or even youtube (I've seen people with ~500k subs, and awesome view counts talk about this) have full time jobs outside of youtube. It's really interesting that they do it as a "hobby" and on the "side" they are making more than many people make with full time jobs.

I think it's best to approach anything like this while having a backup and a real stream of income. Have a job, go to school, work your way up in the workforce, and don't think about going "full time youtube" unless you can actually support that kind of thing.