I passed my PPL Skill test in August 2010, after a 18 months of flying around the South east I decided to give the ATPL exams a go.
I signed up to Bristol Ground School on a distance learning course which took me 18 months to complete the 14 exams. I couldn't begin my commercial flight training straight away due to work and financial constraints so I didn't start the CPL until June 2014, which took 3 months to do. After that I did the MEP rating which only took 10 days, followed by the IR which I began in November 2014 and passed in Feb this year.
So I believe it depends on your situation. Having a full time job, mortgage and a family certainly does slow you down but if you want it then there is nothing to stop you achieving it, even if the time frame is longer.