Right answer is both.
The most earners of STEEM are the investors, period. It is the reality of cryptocurrency, in fact any cryptocurrency. For example, whoever, bought BTC at $100 or LTC at $5, able to sold at $10K a BTC and $200 a LTC are the real winners. Even STEEM was both 10 cents and $8, theoretically, one with $10K could have bought 100K STEEM and sell it for $800K (i.e. almost a million). How many bloggers will be millionaires someday, if they just have started blogging today (without investing)?
However, what effort investors put: learn some skills(i.e. gut feeling or prediction) and hoard some extra cash (i.e. savings through other work). They are not PoW miners or Proof-of-Brain (PoB) bloggers. In fact, the investor class is the richest class in the world. They control most of the world's capital. Indirectly, they control the whole economy such as our jobs, interest rates and living standard.
Therefore, when both STEEM and SBD drive up above $5, the average bloggers are earning handsomely but when they sink below $2, bloggers are floundering. It depends mainly if the content creators live on the earning on the STEEM blockchain.
STEEM, even the all cryptocurrencies are in the mercy of Investors (or speculators). In fact, they have more control over blogger's living standard than the stakeholders of large company (e.g. Intel) have over its employees. If investors class lose their hope in a stock of a company, the company will cut it jobs.
In STEEM blockchain, earning will drastically drops, if investors sell their holdings very cheaply. However, most jobs are safe and at least, earn steady income while they are functional. In STEEM blockchain nobody will be fired unless STEEM's value goes to zero, which is very unlikely. But earning can really sink to a level that can be felt like joblessness.
Therefore, I personally recommend to understand and learn investing along with blogging. For example, sell your STEEM or SBD during bull run, buy them back with a portion when they sink. For example, one can sell STEEM/SBD above $4, buy half of them back at $2. This way, half of the income can be consumed. However, it is only possible for the bloggers who are not fully depended on STEEM's earning.
If a blogger is serious about overall cryptocurrency, I would recommend to learn trading or investing. If they have save up some decent cash, you can hedge your earning on STEEM through trading during the down time. Also, I would recommend to learn about mining and staking. Mining is very risky and however, if one can manage a decent GPU and cheap power, it is worth trying. These days ASIC mining has become expensive and risky.
On the other hand, staking (e.g. PoS) is another form of earning where one has to buy some amount of coins (e.g. 10K SMARTCASH), lock them in a wallet and then can earn some coins daily (20 SMART). Interestingly, SP delegation to bots such as @smartsteem is very similar to staking.
Cryptocurrency is a very volatile asset. However, volatility has created some opportunities for shrewd investors and traders. And, depending solely in blogging skill in Steemit (i.e. one does not have at least dolphin level SP) for earning (living) is very inconvenient, specially, during the long bear trend. Therefore, it is recommended to learn some trading and investing or mining and staking skills to hedge some earnings if one is serious about living on cryptos.
Disclaimer: This opinion is not a financial advice, it my personal perspective and opinion. Please seek professionals for financial decisions.
Image sources: Most images are open sourced (e.g. Pixabay, Wikimedia etc.) with Creative common license. Some images are used with due courtesy to respected owners.
Thanks for reading.
Cryptominer since 2013, occasional trader and tech blogger