Throughout Puerto Rico's History there were multiple proposals to slim down the number of Municipios, but non have been successfull. The Map below is of the most detailed proposal, from a PNP Legislator in the 2009-2012 term. It sought to slim the number of Municipios from 78 to 22.
The Resources linked are the events when the media has discussed the proposals to slim down the ammount of Municipios in Puerto Rico:
2009 Attempt to reduce the Number of Municipios:
2017-2019 Attempt to establish Condados (counties):