This questions is asked time and time again and answers very from post to post. The factual answer to this question is yes, people can make a living with landscape photography. The larger question is can "you" as an individual make a living at landscape photography.
The facts are that anyone with a few hours and digital camera can take a landscape photograph. The shear volume of people taking photos ensures that at least some quality photographs will be produced. Based on a estimation from an article on Infographic there were 1 trillion photos taken in 2015.
If you assume that .001% of those photographs are top shelf stunning work it would be 2,739,726
masterpieces taken every day around the world. If 10% of those are landscape photos that could mean 273,972 hit the market every day. Your photo would only be 1 of those 300,000 photos.
The question you have to ask yourself is "Am I good enough at producing quality work every time I hit the road to put food on my table?" Better yet "Do I have a history of selling enough work that if did it as my full time job I could make a living?"
Take this example, you have 100 photos that bring in $150.00 per year. You have collected those photos over the last 5 years. If you calculate the time used to take each photo at 2 hours. This could include travel time, color adjustments etc. You have used 200 hours of time to create 100 photos. Now you want do this as a full time job. If you calculate your photos per year based on a normal work year. 242 days at 8 hours a day is 1,936 hours divided by 2 is 968 news photos a year.
So each year you add 968 photos to your collection. Based on your historical performance each photo will earn you $1.50 per year. Lets map that out for the next 5 years.
In order make a living on landscape photography you must make either a significant amount per sale or a large number of sales. Both are difficult to do. I would never discourage anyone from attempting to make a living at landscape photography, but be prepared for the long road to success.