I worked on my first blog and had the blog online for 5 years before it started making a good enough amount of money to live off.
I worked hard to get the blog to where it was making money and I worked for those 5 years without hardly any pay and the first year there was maybe $10.00 I earned through Adsense.
But all that hard work in the beginning working on the blog writing blog posts and promoting the blog and blog posts paid off and continues to pay off.
You still have to continue to work on your blog though if you want to continue to earn a living through blogging.
A blog and website is never finished. If you don't continue to write for your blog then your blog will go stale and you'll lose your google search rankings and current readers.
Your current blog readers need more content to read otherwise there will be no need for those blog readers to come back.