Since we took outside investment that period is about 5 years. Without outside investment it will take longer, maybe 10 years. Many potential hires don't want to wait that long. They might wait 10 years but only if you get a substantial windfall at that point, not the first small profit share.
Partnerships are more common at consultancy and finance firms where labour generates direct profits. I think they are less suited for product firms where the labour comes years ahead of the revenue. A liquidity event is a great way to bring the 'windfall' forward.
Of course things are not black and white. We choose a 4 year vesting period https://about.gitlab.com/handbook/stock-options There are startups now doing 6, 8, and 10 years. We didn't have a good reason to deviate from the norm, so with our vesting time we stuck to what is usual in order to be an attractive employer and hire the best executives.
But we also wanted to make GitLab a great and popular solution. For this we need the best marketing and sales people. When we tried to hire those they wanted options in the company. It is not fair to give options if it will take very long to cash them. So we needed a liquidity event in any case. In that case it was better to take outside investment so the chance of getting to IPO was higher than without it.
If we would have not gotten in we would have continued GitLab and probably applied again for the next batch.