Ok I'll add to this, from Both Sides but mainly for Twitch
Ok the Viewer Side
1 I do sub to a couple of streamers, but I am very select as to who they are. There people who I personally know and have also helped me a lot as well.
2 If I can, and again based on the above I have dropped a few quid to them, or got them something from the games gift shop / Steam.
3 I never feel pressured to do the above, on the basis that there are other ways to help streamer's - Host's etc
Generally, If I know them, like them and have spoke with them before I'll help them if they ask for a decent reason or I have soem spare money - a lot of the streamers I know are small streamers like myself with sub 1000 followers and very rarely ask for anything.
I won't actively support someone who has what is termed a begger bar right from the word go (A begger Bar is basically when you see they have a goal for fund's and have maybe 100 followers at most - They are in this for the wrong reason)
From the Streamer Side
Firstly the last comment on the pole I find harsh and unfair - Though I will balance that by saying I understand why people think that, especially with the number of people new to streaming with the begger bar on display as stated above.
1 - The vast majoriy of streamers are unpartnered - so they don't get the sub button from twitch. So if they want to earn money from it, they either have to be very very good / ESL Pro level to get viewers and support from people / companies or they need to offer other methods.
2 - Sub's v Follower - The quote above regarding having 12000 sub's - if thats a number you see next to there name then thats not true - they will have maybe 12000 followers, and a % of those will be sub's, unless that streamer choose's to disclose the number of sub's they have through Twitch. A streamer I know as 25k followers, but only 600 subscribers to his channel. 500 Sub's is the level normally at which a streamer can think about going full time as it is roughly the same as about a 20k wage a year. But this does move a lot, as not everyone carries on there sub, some people sub for just a few months and stop.
3 - 'Its not a real Job' - Speaking as a streamer who also has a full time Job, I put more time into streaming then I have ever done in any other Job I have had - Inc retail sales. You are basically the Broadcaster, All the Production crew roles and the Technical crew in one. You will spend maybe 2-4 months tweaking your software settings to get your stream right, and then the rest of the time's you stream making small changes to balance your stream. When your streaming you ahve all the interaction with the people watching, keeping aeye on chat, thanking people who host, follow, sub, answering viewers questions, taking viewer request's to see any new content you may have.
Off stream, you'll be liasing with Game Developers / Community Managers, providing feedback to them from your audience's, getting updates on new product's coming down the line.
If you get noticed even wider, then you will also be dealing with PR rep's for other comapnies who want you to promote them or affilate themselves with you. This in it's self is a huge minefield, who do you pick, what fits with your channel and viewers etc.
4. Not all streamer's are in it for a paycheck and to go full time. Some are they for that and that alone - and you can easily tell who they are. Some have got that way, because they are the most well know in there choosen Game, and as stated above have built there life on it.
Those that go full time because they have grown large enough and stable enough to support themselves, normally do so in the knowladge that a streamers carrer is very much linked to the game's life span that they stream.
I hope the above makes sense, but I'll happily field questions and answer were I can.