@someunregpunk:
It is not because Ryouta does not has the guts to do it but because he even fails to notice that he already is in a situation where he has girls around him with whom he could do the same things.
In other words:
It is because Ryouta is simply far too dense - like most of the Japanese MCs.
I think that "being dense" is the Japanese authors' easy explanation as to why their MC does not end up with one girl but a harem.
Their logic seems to be:
MC being dense -> does not realize that a girl likes him in that sense -> does not confess to the girl because he does not realize it -> continues the relationship on a friendship level -> meets next girl -> start from the beginning unless author's goal of X girls is reached.
==> If goal of X girls is reached switch to harem creation path by girls confessing to each other that they like the MC. '
Then instead of fighting it out for him they "decide" to all confess together and with the intention of becoming the MC's harem.
That is the most used pattern for Japanese harem stories.