The problem Foakes has got apart from being in competition with two other outstanding batsmen/wicketkeepers is that the skills he is showing in this test are far more redundant in English conditions when most of the time you stand 25 yards back waiting for nicks from medium/fast bowlers.
He has always been the best of the three standing up which is where you judge a keeper but Butter in particular is a massive part of the leadership of this current team and probably the most important point is he is clearly Roots man and the captain should always have the final say on picking the side.