Ada and Pascal are both languages which allow multiple consecutive parameters with the same type and also use `name: type` syntax. I agree, even when using Ada/Pascal with colons its difficult to mentally parse.
It's especially terrible in C and C++, where you need to be on your guard for whether all the variables are being declared with the same type or whether some are pointers. Even in languages without this quirk though, I find it still slows my comprehension.
Unlike readability, conciseness of code isn't a virtue in and of itself. I see little upside to multiple-declarations, but clear downside.
Language trivia: the D language does not follow C's rule, instead it guarantees all variables in a multiple-declaration statement all have identical type:
int* x, y; // x and y are both pointers to ints
var x, y *int // both pointers to int