Thanks for sending me that post. It gave me a more realistic view in seeing those numbers. Quite concerning because there's a huge difference between activity and the number of users (considering what was given there is the number of those who posted at least one time - on the active vs registered graph).
Regarding investing your time, this will really be up to you. But you're new so I suggest you give it a try. Some get really lucky but some like me have to work harder. It does take a lot of time - posting, commenting, networking through various chat channels, etc. I had some discussions about this with different people and most have agreed that one has to have more reasons to stay here than the reward (to support a community for instance).
I also recommend you read the post by @davemccoy which is about setting the right expectations for newbies and you might get insights of some realities here https://steemit.com/steemit/@davemccoy/if-ifs-and-buts-were-candy-and-nuts
I also recommend you use the newbieresteemday tag since you're a newbie. The vote is small but it's additional exposure.