The quality of the post should matter more
When new posters are ignored it discourages them from posting again and you get what you have now on this board....probably 10-20 posters make 70-80% of the posts.
I would guess that those numbers are skewed; there are definitely more than 10-20 posters that bring a lot to the table, in terms of both quantity and quality, here.
I do agree that quality > quantity. However, I think that a lot of posters recognize quality. Sure, the "big name" and/or more visible posters (i.e., those with recognizable avatars or signatures) get more attention as a whole, but that doesn't mean that posters with smaller post counts are ignored.
I can think of several posters who have started posting since the trade who I can think of off the top of my head, because they've mad themselves known with the strength of their arguments (good or bad). Similarly, I've seen relative "newbies" be embraced in places like the CB Draft, etc. It's all about putting yourself out there; posters who repeatedly make quality posts will get recognized, I think.