Salem

I have come to the conclusion that new chars have higher chance to get rare items such as 7 use inspirationals, egg sacs, needles etc.
I know mining has a mechanic that makes it harded to get a cave down if you mine a lot so I was thinking the chances of finding rare items have a similar algorithm. Is this true?

Probably just RNG.

BUT, I can say that whenever I have gone foraging on a new alt I have always found atleast one WSS and a few rare inspirationals, but never have I gotten any of them on my main.

I noticed this, too.
Last time I made new character I found 2 7-use-inspirationals in the tutorial.

New character got me 2 egg sacs from 70 spiders and on my main I cant get 1 from 700

Maybe new players are a little more 'lucky' during the time they don't suffer from insanity.

I think it's been that way before they were granted the sanity time. It makes sense, though. This way higher developed characters have more of an incentive to buy these rare things from newer players. Maybe they made it work like this with the patch that made those inspirationals 7 use and more rare?

I always assumed it was just that the rare inspirationals are the last to get "checked". Like after you get the skill that makes more stones and flint show up, and more mushrooms, and more flowers.... The odds of those things all go up, so the remaining odds of a rare go down?

Hmm maybe you have more programming experience than I, but how likely are the odds that I get a mushroom when I pick an autumn grass from grassland?

I have also noticed this new char luck and assumed it was that. Something comparable to the Lucky skill to give a new player a little start-up kick. Also, I don't know if the Lucky skill actually increases rares RNG.

I guess I was thinking of Gourds and Singing Old Logs which show on the minimap

While it would be an interested mechanic it would also encourage vets to make new characters to spam farm rare things. So no, the odds of rare things dropping are dependent only on how lucky you are.