Some people have pointed this out several times.

I now believe that having a massive field with people still jumping in is hurting focus on the democratic primary race from voters.

The DNC maybe should have tightened up entry races, for example, only polls from closed primary or caucus states count in the polling requirement, and each candidate in debates must raise $4 million dollars and have 200,000 unique donors. Something to quickly knock some people off the debate state and let the frontrunners debate.

I believe that all the complaining (untrue) about the DNC "fixing" the 2016 race lead DNC leaders to implement a format that would blunt that criticism, but which has led to crowded debates so far, with some people who shouldn't be there on stage.