i am a novelist and worked as an editor  and you nailed it at least for me using commata a lot is a persitent issue with my writing and i often break up sentences during the editing process  though i am not sure if this is not also a sideeffect of adhd-drugs like amphetamines as they tend to trigger very intense toughttrails and enhance your workmemory so you tend to write longer sentences nonsense spread over long sentences and a lot of commas are a also common trademark of hardcore amphetamineheads like aynd rand or the later pkd