-e and -y are very common masculine plural endings, other are -i, -owie, -a
this website suggests we have 102 types of declension for masculine nouns. Most sources claim we have 5 patterns for consonant ending masculine nouns.
most resources here work for declension too
well you didn't answer the actual question – is it kapelusze and not kapeluszy because it's inanimate (one)?
I do not why, but for some reason, I thought the question was, why isn't the plural nominative=accusative form of kapelusz, ending with -y.
the reason why it is accusative =nominative here is, because it is not masculine personal plural noun. All masculine inanimate nouns are also not masculine personal, so you are right.
Masculine (except personal) and feminine plural nouns take -e after sz, cz, c, j, ci, dż, ż, zi, rz, si, ńi in nominative and accusative cases.
kapelusz (a hat) - kapelusze (hats)
kupiec (a buyer) - kupcy (buyers)
The following verbs distiguish habitual from progressive action: biegać/biec, jeździć/jechać, pływać/płynąć, nosić/nieść, wozić/wieźć, latać/lecieć.
Nosimy (habitual) - We carry / we wear
Niesiemy (progressive) - We are carrying (Exception; it does not mean: we are wearing)
We are wearing - Mamy na sobie or Jesteśmy ubrani/ubrane w