While I definitely support this policy change, promising this again five years after he was supposed to already do it is too little too late.
Trump targeting birthright citizenship with executive order (2018)
https://www.axios.com/2018/10/30/trump-birthright-citizenship-executive-order
You are right, but I give him some slack coz he was a newbie elected politician. He may have learned a lot how DC works, and it is entirely possible (but not guaranteed) Trump will be more pro-active in his 2nd term.