I feel like slideshows exist to save the author time at the expense of the participants. Given that presentations always have more viewers than authors, this is rarely the right tradeoff.
Ppt decks in large companies usually aren't really slideshows. They are really meant to be printed / viewed on an individual screen, and is fundamentally enforcing a bullet point style and a lot of visual elements (charts, diagrams) as opposed to a long text only memo.
But over time people feel the need to stuff more things in them and you end up with 40 slides decks that defeat the purpose.
