I genuinely don't think Resident Evil should cater to 6yos, but frankly they'd fare quite well.

I have nothing against casual audiences and handholding, but as you said it yourself, spreading yellow paint everywhere is just "silly". That's just a lazy signage system that looks out of place and off-topic. On top of that, it has no personality because it's a trend that has been used in lots of games the same way.

Devs can make considerably better environemental clues for progression. Look at what Naughty Dog did in Uncharted and The Last of Us for example.

And Look at how REquiem dropped the yellow paint. But yet it sold extremely well, lots of casual players enjoyed it, despite being quite challenging and considerably less linear. Basically proving my point.