Acquired last year and decided to get out of the space for the following reasons:
1. Traffic verification- understanding if traffic is largely bot driven or truly human
2. Search volatility (this one is huge especially for early sites)- Google makes >300 updates annually w/ typically 4 main "core" updates. These updates can be especially problematic when your revenue is projected at x but Google's search update moves you down in rankings (opposite is true if move "up" in rankings).
3. Lack of revenue diversification- many lower cost to acquire sites start with ad revenue. Higher quality sites have private label products mixed with ad options (and even SaaS tools for sale as well depending on niche).