Have worked as both PM and developer and now run my own very small software company
A) two years senior engineer is like one of those consulting companies where everyone in 2 years becomes DIRECTOR
B) In two years most new programmers have not even gotten their heads out of their asses
C) You should refer to Outliers
10,000 hours to master a task
And to that add
10,000 hours to make your first masterpiece
D) Even if you have managed to get 10,000+ hours of coding experience in high school and college and somehow become a very good programmer (which less than 3% of CS grads do)
it will still take you 6 to 10 years to get another 10,000 hours of working on masterpieces and making really good software that you can ship and make money from
E) a title like 'Senior Software Engineer' should be reserved for someone who has MADE and SHIPPED and GENERATED MONEY from a very good piece of software or some software product
F) Personally, I would think any company handing out Senior Software Engineer titles after 2 years is a joke
Between all the places my friends and college mates and I have worked (Microsoft, Google, Amazon, Facebook, Oracle, etc. etc) I can't think of any place that handed out Senior Software Engineer like it was candy
Even very, very good programmers had to EARN IT