With much respect I would ask you to read those texts again, for they do not speak of 'prayer meetings' as we know them today. Rather, they speak of special, impromptu gatherings of people with a like mind . That is, God prompted each one of them to meet for a specific purpose. Something urgent and important was going on and the people concerned all had the overwhelming, God-led desire to deal with it, by going direct to their Lord in prayer. Not weekly, but as and when needed.
Prayer is meant to be impromptu and offered at any time.
Secondly, at these prayer meetings, the 'prayer warriors' always take pride of place. The question is tough but necessary. Thirdly, these prayers are either very broad or very personal - the first is useless and the second is not for public ears. When the apostles and others prayed together, they prayed with one accord about a single urgent matter. We are not told that there were regular meetings.