Consulting would offer an avenue for growth. If you do well, you can hire more people and make more revenue.
Both of Mozilla's likely search revenue partners in the US are also competitors and both use anti-competitive means to push their own browsers.
Building their own search revenue stream isn't going to happen on $400M annually. And I don't think Yandex or Baidu are planning to seriously address the US market.
Also, I could be wrong, but I thought ad spending was way down this year.
We're talking 10s of millions here. Plenty of consultancies make 20million+ per year in revenue. It could even be the start of a new branch with value adds like Confluent, Databricks, which are more in the range of $150-200million.