I personally did not become JNCIE to Join Juniper.
The JNCIE opened up so many career doors on my way that I would never want to miss it.
The amount of CCIE's is significantly higher - but that makes the JNCIE so "special" compared to the mass.
I don't think, that you have to be a JNCIE to join Juniper - have you applied for open positions at Juniper yet?
Vendor certifications like the JNCIE are NOT about getting hired by that vendor but learning deeply how to utilize the vendor products in the best and most effective ways. This can be at vendors, partners that sell vendor product or at end user companies.
Hiring is a multi factor process. In my experience hiring managers look at the sum total of broad areas of candidates and pick the best OVERALL choice for the particular position. The major factors I have seen are:
One of the weaknesses in most hiring processes is when you don't get a job there is generally NO feedback. So you have no idea why you are not the best candidate and what if anything you could do to improve your odds. This is especially true of the "good fit" areas as they are so subjective.