This all depends on YOU! I asked this question a while back and got some great feedback. I decided to quit my job which I was making close to 45K a year to run a real business online. Many people said you should have your debt paid off, many months of savings, multiple revenues and so on. I agree with this in a way! However, If you are like me and had health problems and dread going to your 9-5 and treat IM like a real business... I would say go for it! I have a husband who works a 9-5 and carries the family health insurance which is great because self employment insurance is expensive.
I have many years IM experience and only have 1 income stream with just my online business. I do agree you should have a backup income stream but people are making a living off 1 online business everyday. You can check out websites being sold where people have been making 10K-50K a month for years off 1 website. I wouldn't rely on all organic traffic... invest in many PPC platforms and make sure your ROI is good.
For those of you making a full-time income online, your telling me you have no debt, many reliable income sources, months or a year of salary saved up, investing in 401K or whatever you invest in? I know many IM's do have this luxury but many that are making a full-time income don't including myself. My business is starting to take off in the 5 figures a month range and I don't live above my means like some IM's you see on YT.