In fact I'd go further and say it's pretty much industry standard for recruiters to go missing/contract ending mid-offer. It might sound aggro, but if you think you have an offer coming, it's not awful to email anyone you might know inside a company to get an answer.

Heck, I don't think I even mind telling people it didn't work out, so if you get in this kind of mess with Google, I'm happy to track down errant Google recruiters for you for them to officially turn you down, or happier still, get you that offer that is waiting in some stalled process.

Big companies can be challeging to interview for. So many moving parts that translate into an offer. pre-interview, interview, referrals, manager and exec review, headcount allocation, comp negotiation, etc. etc...