If you take a wander through the Mosquito section on this forum you'd find a few old girls still actively sailed even tho their build dates are ~mid 70s or earlier.
Number 126 was recently purchased and although not sailable as she was it wasn't a great deal of work to put her back on the water.
My first Mozzie was #245 and it was bought by my dad in 1972 and he sailed it through till 1977 before handing it to me.

This old design still sticks it to the modern boats to this day, combine that with what most mozzie sailors seem to have... that NEVER GIVE UP attitude and you have a very strong fleet of boats that have been around since the early 60's with very little change throughout the years.