It's always possible to acheive 6-digit net worth by 30 without having multiple streams of income. I am a teacher at a well-paid area and focused on cutting my spending to bare necessities (with the occassional coffee or fast food, but only once a week for each).
I started investing in 2018 and have around 85-90K net worth (depending on how the market is doing). I'll be 28 in a few months, so the goal is acheivable, depending on whether you go to a low-cost university and apply for scholarships to avoid going into student debt. All things are possible when you do research.
For me, it's not a matter of having enough money to buy things without a second thought. Rather, it's about having enough money to not live in fear of being fired or laid off, like many people did during the pandemic. Fortunately, my school district didn't furlough anyone, though some articles I read said about half a million teachers were laid off during the beginning of the pandemic. For those teachers that didn't have an emergency savings account or have any money invested, I felt horrible for them. Had I been laid off, I could easily survive for a few years living minimally off of my investments until I found another job.