"Will it? Forever? What are you doing to ensure that?"
Because most consumer startups fail. The ones that get bought out usually end up sunset or neglected. Even the ones that IPO often alienate users by chasing quarterly earnings (evernote/dropbox/pinterest).
An important detail that none of the reporting I've seen has mentioned: Tesla got upwards of $750 million in subsidies from the state of NY for putting the Gigafactory 2 in Buffalo.
The condition was that they had to support 1460 jobs. Last I heard they were around 1500, so it's reasonable to believe the analyst jobs are only located there to avoid paying fines for breach of contract with NYS.