I believe it is not much harder to make money today than it was say 10 years ago. If, the person takes their time to put in the keyword research, and find buyers that want the many new affiliate products available to market, a person can make a income from doing this type of work.
It is work, and for that reason the person should treat it as their job, regardless if they are doing this out of their homes, or not.
What we do have today, is all the social media, and backlinking methods, which can actually make it easier then it was 10 years ago to get traffic, and customers to our offers.
I do not beleive it will get harder as more people turn to the online world to shop, and make their everyday needed purchases. This can actually be very benefical to those business owners who stick with it to supply their needs.
However, the business owner will have to work a little harder to provide the unique content, and services that the new customers coming online expect from store owners, than they had to do in the past to gain their trust .
Additionally, some old methods still work, but again they do take work to complete. I also agree with many of the answers that have already been supplied here, however for anyone reading them, they should not be worried about getting started, but actually learn from these answers, and simply get started on providing their own customers with the needed support and services to thrive in this growing industry.
Hope my answer helps to answer your question on this topic