Thank you for all the replies!
@
archaicwarrior: WTF?!?
So you are living in a complete different world, with almost no lords alive from the beginning.
And if you go to DB > filter wanderer > filter age ... there are some young ones?
And yea, I did not ask for support since I'm playing on Beta branch (1.7.2) and I can accept some bugs.
But I've testet further and in another run (Sandbox) it replenishes wanderer - a 21 year old just arrived - makes sence because while playing difficult situations you lose wanderer companions or promote them to lords.