(Dictionary/Potential/Negative-ない)-Form VERB + ようになる as “it has become that”
This grammar construct is similar to the (Dictionary/Negative-ない)-Form VERB + ようにする grammar construct in that it expresses a change of state; however, it expresses this change intransitively. The emphasis in this grammar pattern is on the actual result, as opposed to the means it occurred.
16 sai no toki ni, unten shi hajimeru you ni narimashita.
(It has become possible to start driving at 16 years old.)
Nihongo no manga ga yomeru you ni narimashita.
(I have become able to read Japanese manga.)
Ano hito no kao ga (oboerarenai you ni/oboerarenaku) narimashita.
(It has become that I can no longer remember that person’s face.)
*When using a Negative-ない-Form VERB with this grammar construct, the technical construction is ないようになる, however なくなる is more natural and widely used.