Preach the word; be instant in season, out of season; reprove, rebuke, exhort with all long suffering and doctrine. For the time will come when they will not endure sound doctrine; but after their own lusts shall they heap to themselves teachers, having itching ears; - 2 Timothy 4:2-3
Whatever means you use to get people into the church, is precisely what you must use to keep them.
If you get them with a 'religious circus' then you must keep the circus going—you must keep up the entertainment.
If you get them with biblical preaching and teaching, then that will keep them and you will not need the entertainment.