I'm an online marketing manager. There is no easy way to answer this question, but maybe a little industry knowledge will help. What is happening on this site is "Contextual Advertising" which is different than "Search Engine Marketing" (a lot different). Each industry, and and each product/service within that industry has a different average "Click Through Rate" (CTR).
The CTR is calculated by dividing the number of clicks by impressions (every time the ad is shown is 1 impression). So 2 clicks out of 100 impressions is a 2% CTR. Generally speaking, with Contextual Advertising, you see a less than 1% CTR.
CTR is directly affected by several things. The content of the ad must be directly inline with the intent of the user. The closer the better. So in this type of environment (hubpages) you can guess or shape the intent of the user by writing an article that will be directly relevant to the ads you want to display. This will increase CTR.
Then you have to factor in the fact that HubPages take 4 out of every 10 impressions. So all projected numbers must be reduced by 40%.
This topic is huge, and I could write a lot more about it, but will leave it at that for now. So in short; if those 5000 hubs are crap, then no, you will not earn $100 per day. If they are pure gold, rich with relevant advertising, and get a good amount of traffic, then sure, $100 per day is not unreasonable.
Be peaceful on your way,
"I am Another You"