No mfg cares about warranty. It's just another peice of advertising.
If you ever try to invoke it, you'll have to pay shipping or restocking or some sort of fee that will be 2/3 the replacement cost.
Or they just won't honor it and will weasel out based on any number of exclusions.
This is partly because cheapskates will run trash oil filters or junk oil to save $10, and then figure "warranty will replace it", and so abuses like that become prevalent enough that manufacturers just say "to ehll with our customers, they're morons" and partly because it's just cheaper to say "no".
You nailed it though - people will always go with the cheaper option and feel like they got a deal - anyone making higher quality will only ever get about 10% of the market if they're not super competitive on price.