In the past it was possible to reach call stack depth 1024 in EVM. However I heard that now it is impossible due to gas costs.
Is this true?
It is not possible to reach callstack depth 1024, because the max forwarded gas is always 63/64 of the total available gas. The block gas limits need to be of the order of 1e8 ((63/64)^1024) in order to reach this depth.