Basic? (a common 5-letter word, for sure)
Something with a very low pH,
In chemistry, a basic compound is one... with very high pH. (It has very low concentration of hydrogen ions, but pH is a reverse log scale.) Oh well. I'm banking on this being a typo.
though not alive, I evolve as I age.
"basic" also can mean at a low level; as you learn, you can get more advanced.
My grandfather was used in building;
Now we let BASIC be a programming language. It was indirectly influenced by Assembly. (i.e. "building")
My father, though smaller, was ground-breaking.
FORTRAN is ground-breaking and a highly influential programming language. Also, as time goes by and computational power goes up, computers start getting smaller.
Though I'm smarter,
I'm not much safer,
for sometimes I'm crashing and burning
BASIC is a high-level programming language but can still crash.