I only knew one person who made E-5 before his 4 years was up.
I was an E4 out of boot camp.
It often depends on length of your enlistment and what you sign up to do.
Sign up to be a swabbie with no guarantees of advancement and you get what you get.
It would be interesting to know what this fellows rate was.
I think someone said he was an AE Aviation Electronics Technician, That is and advanced rate and he should have been an E5 within a few years.
I was taking and passing the E6 test within 6 years.
A couple of guys in my shop did it but they were A school grads. When I was in {76-80} they liked to use E-5 as a re-up carrot. Chief offered me E-5 and $15K to try & get me to stick around. LOL
E-5 is the best rank to have in the Navy really as far as what is required of the rank. You're not doing the trivial dirty work, usually not sent to mess cooking etc unless as a supervisor, and in most cases they don't have the headaches most First Class and Chief's deal with on bigger ships.