Why do learnsets change between evolution relatives?

Question

I have been playing Pokemon since B/W but I am pretty new to the ins and outs of Pokemon. I was reading through the Pokemons learnsets and I was curious as to why certain Pokemon learn moves that the pre-evolution didn't know.

For example, why does Stoutland learn Ice Fang, Fire Fang, and Thunder Fang at level 1 when its pre-evolutions cannot learn it? Stoutland evolves at level 32 so how can it be at any level below that? I know this is a stupid question but I have no idea why this is or how this is achieved. I searched but it only says this on Bulbapedia.

"Sometimes, Pokémon's movelists vary between evolutionary relatives. This often is tied to a secondary type gained or lost on evolution, but can also provide incentive to prevent a Pokémon's evolution to a higher stage."

I am asking why this is and how it is achieved. Thank you very much

Comments

It can be caught in the wild or move tutored/remindered to learn it.

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Please answer the whole question, a la "Why do earnests change?" Try to keep answers at 2+ sentences to make them look bulkier and less like a comment, as a rule of thumb.

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To answer the Stoutland question, I think that Game Freak wanted to make getting good moves a challenge to get, like fishing for Luvdiscs and stealing their Heart Scales. The games wouldn't be very fun if you get good moves easily to sweep through

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The rules say keep answers simple. .. if the answer is simple, why add unnecessary bulk?  Anything beyond what I said would be opinion and speculation.

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I just read through them, where does it say that? It does say this however:

"Putting some effort into … answers is more likely to make them better than other answers."

I'm not trying to start a fight, I'm just saying that single-sentence answers make it look like you put no effort into it. Sometimes the question calls for a short answer like that, but usually it's good to have more than 14 words.

Answer 1

Some Pokemon can be caught in the wild with their level one moves, and there is also the move reminder who can teach Pokemon their level based moves in exchange for a heart scale... It is unknown why Gamefreak chose to do this gameplay mechanic, but probably to increase the challenge of Pokemon training.