It's not the only factor leading to troublesome architectures of course. Still, if state and thus data is wrongly handled, you're indeed on the wrong track.

There's indeed value at using the URL to store some of the frontend state. This is too often forgotten.

Excellent article in French from one of the most influential people of the agile community in France. He delivers an interesting story about how state agencies started to apply some of the agile values and principles but how unfortunately this wave is already receding.