I have over 100 sites of which 60 blogs. The blogs generate 80% of my income and that's more than what you mentioned in your first post.

I think it's easier to get 1000 visitors per blog than 60K visitors on one big blog. The past 2 months, I have merged some blogs because I wanted to spend more time on certain blogs, but so far I have to say that this wasn't a good choice.

Blog traffic is far more valuable than tube traffic, however it's easier to grow in tube (in traffic numbers). It's all a numbers game.