Perhaps worth noting that none of that is langauge syntax, it's library syntax. mapOf takes vararg pairs: Pair<K, V>, and then the 'to' operator is an infix fun

Perhaps worth noting that none of that is langauge syntax, it's library syntax. mapOf takes vararg pairs: Pair<K, V>, and then the 'to' operator is an infix function that makes a Pair<K,V>. So you could trivially do your own listOf or mapOf that creates whatever data structure you want, whereas languages with special syntax for this tend to hardcode the result of it. That's a valid choice, sure, but just that there are tradeoffs here rather than it being obviously better one way or the other.