The short answer is no. The difficulty in making this model work is that cost of generating a sale must be subtracted directly from net from single sale. Given multiple products, this cost is distributed over a number of sales, and thus is less per sale. More important, an existing customer is your best prospect for a subsequent sale.
While there are exceptions, such as a successful affiliate program marketing say a private site, a single product site will produce modest profits. While they may be sufficient for one building a hobby or personal site, they are unlikely to produce a livable income.
If you have a single product site, or are planning one, path to increased profits lies in adding additional products. Customer loyalty is goal. You want all to return for more. Given shopping bots and so many web shoppers determinedly looking for price only, building repeat business can be difficult. Still, even though many buy never to return, your best prospect remains previous customers. To take advantage of this, you need additional products of interest to them.
Expanding A Single Product Site
As you consider adding products, be clear about your target. Be certain you have an accurate picture of your Perfect Customer. Every offer added to your site must be perceived as being beneficial by your target. Further be alert to impact it will have upon your position in your market. Negative just won't make it.
If you try to sell harmonicas to an established target of opera lovers, your credibility about opera will drop dramatically. Serious visitors and subscribers will quickly disappear.
Note reverse is equally true. Try selling opera to harmonica fans. It won't fly worth a hoot.
Beating Up On The Competition
Another grand benefit in expanding your product line is strength it adds to your position relative to that of your competitors. While such expansion needs to be within constraints of your position and target, a broader range of products can greatly increase perceived depth and scope of your business.
Ebooks As An Example
I recently compared all ebook compilers I could find. (For details, send email to mailto:email@example.com ) There are about a dozen that compile from HTML code to a Windows EXE file. They all face direct competition from Adobe Acrobat, which compiles to a .PDF file. And there is plenty of indirect competition from handhelds, such as eBookMan. (Then, of course, there are hard copy books, still much favored.)