Firstly, there is no correlation between the quality of writing (writing skills) and the capacity to make money.
Secondly, it is not the number of hubs that is relevant, it is the number of people coming to the hubs.
The better the SEO and the better the backlinking undertaken on a hub that is popular in keyword terms, the better the chance of getting significant traffic.
Those that know state that to obtain an income of $100 / month from adsense you will need approximately 14,000 views from outside of Hubpages. So for $5 / day, $150 / month you will need over 20,000 views.
Amazon earnings run on a different set of parameters. You can earn significantly more from significantly less visitors if you are capable of creating good ad copy and you are able to attract visitors that are looking to buy what you are offering.
Amazon hubs also attract adsense clicks - so double whammy!
If you are able to obtain an Amazon.com account (note that this is the only Amazon version that Hubpages supports) then for the newbie this is the quickest way to get to an earning capacity of $5 / day.
However, be aware, many writers do not achieve any Amazon sales. Amazon hubs must be written in a particular way to attract the right customers that turn out to be buyers.
How long will it take to reach a level of $5 a day? - how long is a piece of string? It is up to you to hone your skills in attracting readers that turn into adsense clickers or Amazon buyers (note, I do not say hone your writing skills!).