Steemit as a full time job, is it possible?

The short answer is yes, because there are already people that use this platform as their only source of income. But the question is, can you do it? (Or, would you want to?)

That is much more difficult question to answer as everyone has a different living situation and lifestyle. In some countries, people can get by with a relatively small amount of monthly income. In others (like parts of the United States), it takes thousands of dollars each month to maintain rent/mortgage, insurance, food, etc......

Lets take a look at a 'whales' accounts here on Steemit, the account owner will not be mentioned but it's not too hard to find out. =)

We will look at this account via the steemworld.org website. We see the 100% voting power is high at $227.43! The last 6 days showing the Curation for each day, Author rewards for their post, Sum Steem and the USD value. (It did not calculate the USD value for the authors post for some reason).
I think the amount of people accumulating ~125 SP in curation per day is a low percentage on this platform.

For starters, it helps to have a little bit of SP delegated to you. I guess something like 760,716 would be a nice start.
So lets look at some numbers $$$ shall we?
Over the last 7 days, this account generated 1,092 Steem for $4,827.
Over the last 30 days, the account generated 4,787 Steem for $21,725. Hmm, If that was guaranteed for the next few decades, I would think about blogging full time, how about you? I would guess that most people would be content w/$21k per month...

But a lot of this income depends upon Steem... Even through the crypto market has been getting bashed lately, the Steem price still held over $3. After the lastest run up, it appears to be in a range between $3 and $6.

I don't think there is a significant correlation to BTC, but it generally follows the crypto market. BTC in Red, Steem in Blue. Crypto market higher - Steem generally follows. (This is a big plus as a higher Steem price will produce more monthly income)

Google trends search for Steemit. With more people on this platform, there are more people that may want to purchase more Steem/SP/SBD. (Which is good for price appreciation) The searches have leveled off, but still near the high. Venezuela, South Korea and China leads the searches.

A note regarding how the rankings are calculated

A potential plus for Steem is the SMT which should be rolling out in the near future
)

If the Steem price continues to appreciate going forward, it will definitely make it easier for people to start using this platform as their income. (And you will not need a few hundred thousand SP delegated to you)

There are a lot of factors that needed in order to make the jump and it really depends upon the persons country, standard of living, liabilities, bills (health insurance), lifestyle, etc... While it is not easy, it is something that is attainable for those that are willing to make the jump.