Why not? In fact it already kind-of does: Go has "default types" for most untyped constants. When you write

    i := 3

> Numeric constants represent exact values of arbitrary precision and do not overflow.

    package main

    import (
        "fmt"
    )
    
    const tst = 1000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
    
    func main() {
        fmt.Println("%v", tst)
    }

See: https://play.golang.org/p/47l5qAsXD5r

> An untyped constant has a default type which is the type to which the constant is implicitly converted in contexts where a typed value is required.

The default type for a number (integer) is int. If you were to add a period in that long string of zeros, the default for floating-point is float64.

tl;dr: Go uses casts to coerce values to the correct types, which means you couldn't get pointers to number literals for non-default number types.