What is your idea of a decent living? It will very likely take several years to reach even a few hundred monthly. You will need LOTS of content that is in demand year round, year in and year out and you must bring in high traffic on a daily basis. If any of these things are off, you would be lucky to earn pennies or a few dollars in a month, let alone a "decent" living.
FatFreddysCat has it right. This should be considered an additional stream of income unless you are literally home and computer bound. There is potential however, even the few hubbers who are making the most of all the hubbers here have been consistent with their efforts for several years PRIOR to earning their highest payouts. Their first year, two or more were likely low paying.
You would need to literally LIVE on hubpages for probably a good 3 to 5 years before you would see your highest payouts and this is with herculean efforts on your end to the exclusion of other things and people in your life. That doesn't sound so great to me but to each his or her own.