Yes, freelancing is very lucrative, if you're a good developer with the right skillset. People are generally willing to give up a lot of money in exchange for a steady income guarantee.
"a steady income guarantee" plus access to good mentorship/infrastructure/etc.
Having done both, I find there's a level of engineering growth that you miss out of by doing freelance work. Most freelance work won't involve supporting millions of requests a day. There's value in that exposure.