The businesses that generated any traffic from organic search took much longer time to get to the same level of traffic or revenue as their counter parts who adopted a more aggressive user acquisition strategy like cold outreach, community posts, viral campaigns, PR, advertisements or other growth hacking methods.
The reason is simple. Organic growth takes much longer time and lot more effort than other marketing tactics.
If you look at successful businesses, most of them went for SEO as a growth tactic much later in their lifecycle. They first exhausted other opportunities to find traction.
The only exception to this are products with little to no competition. In such cases you can easily rise in google rankings and reach a spot where people can discover your product by just searching for it in search engines. Even in these cases it takes 6-8 months for you to get to top 3 positions in search engines and a lot of effort on SEO.