> All tech business plans eventually lead to serving ads

IDK if this is true.

The boulevard of dreams is full of failed/misguided ad-based business plans. Contempt for the business model is sometimes the reason. An implicit assumption that all you need for success is traffic and a willingness to dirty yourself.

There are only a handful of success stories. Most involved a pretty deliberate and tenacious attempt. Success typically involves some very specific and strategic positioning. Data. intent. scale.

No one but Google had google's scale for search ads. 5-10% of the market just isn't enough. You do need tracking but the model works OK even without much targeting. Intent is built in, and that makes up for targeting. But the scale required for viability is very high.

Facebook ads didn't work until (a) they had pushed the envelope on targeting (to make up for lacking intent) and (b) scale was massive. Bing, reddit, etc.... They never had good ad businesses.