26??? You're young! I have a student right now who started lessons with me as a 37-year-old beginner. This person decided they wanted drumming to be a career instead of a hobby, so they found a way to do 2 lessons per week and about 20 hours per week of practice. It has now been over 2 years of this. More than 2400 practice hours have been logged so far, and this drummer is BURNING. Amazing time, excellent hands, solid reading skills,...you name it. This person is absolutely a professional level rock drummer already, and is continuing to get better and better each week. I just watched this drummer do a gig the other night, and man, it was awesome.
Now...the "make a living part" is a different story. I guess if anyone has the drive to do it, it would be this student. But there are a lot of mitigating factors involved. For one thing, original rock rarely pays much money unless your band becomes an international sensation. Most of the people I know who make a living with drums either teach, or play weddings, or play in a cover band, or play musical theatre, or do any combination of these things. Some people simply don't have the heart to do the type of work I just listed. If playing in rock bars with an original rock band is a person's only interest, I could see it being very hard to make a living...unless, like I said, your band happens to become an international sensation. However, if you don't mind teaching lessons (like nearly every famous drummer does), and you don't mind playing things outside of original rock, and if you're awesome at drumming and an awesome person to deal with, I think a person has a pretty good shot at making a living - maybe not a lavish living, but a living.