As someone who hasn't read the books does the plot get worse as the books go on. The first couple were about stopping the return of Voldemort, then the 3rd is more character based. The fourth one is "Look at all this Wizard Crap... surprise Voldemort is back" WTF, why did the Dark Lord go through all the hoops in the first two movie when his resurrection in the fourth one seemed so simple, was this explained in the film?
I'm not sure where exactly it was explained, but after Voldemort's first death at the hands of baby Potter, the Dark Wizard community effectively dropped their support for Voldemort, because they didn't know who or what Harry was, all they knew was that they didn't want to be the one to get on Harry's bad side and end up destroyed. Because if a baby could destroy Voldemort, what chance did any of them have?
When Voldemort revived himself in book 1, nobody helped him. Dark Wizards
could have helped him come back, but they willfully didn't want to get involved (on any side), and they pleaded ignorance.
Books 2 and 3 were about the
specter of Voldemort returning, more than his actual return. The diary was just a memory of Voldemort come to life (later revealed to be an actual piece of him), and Seriously Black was billed as the return of Voldemort's most terrible servant (revealed to be a lie).
Wormtail was revealed as the real villain of #3, which made him run to Voldemort for protection in #4. Since Voldy now had someone,
anyone helping him, his return seemed easy, because it kind of was (although it did involve someone chopping off their own hand). No Dark Wizard was thus far willing to do as much for Voldy as Wormtail did, except for maybe Lucius Malfoy and the diary, but nobody knows what his actual intentions were (and Voldy neutered Lucius soon afterwards by taking/destroying his wand).
When Voldy came back in the graveyard in #4, he thought he had learned from his previous defeats, figured out how to beat Harry, and then invited his cowardly Death Eaters to watch him kill Harry. After two losses, Voldy needed to prove to his troops that they should fear and obey
him, not Harry. He needed to remove Harry as a threat, and he needed to prove that he himself had no weaknesses, lest some Dark Wizard smell blood in the water and decide to kill Voldy for himself, to take his place as the reigning Dark Wizard. In front of that audience, the best Voldy could manage was a tie. Harry ran away. That sort of counted as a loss for Voldy, because Voldy needed to
win that fight.
That's why Voldy didn't make a big move in #5. He hadn't been able to solidify the support of his troops, and he couldn't afford to make another reckless move against Harry, not until he could figure out why he keeps losing. He tried a slow mental attack against Harry, which failed, while he searched for intel, in the form of the prophecy. Also, Dumbledore was unable to press against Voldy's forces, because Fudge was so scared of Voldemort that he refused to believe in the threat, choosing instead to believe it was a ploy, and turning against Dumbledore, so Voldemort got lucky. Fudge bought time for Voldemort to establish his position.
In #6&7, Voldy slowly ramped up his attack against the world, despite his lack of success against Harry.
