A, it's an interesting question. Thanks for sharing.
The short answer to industry tiers is no. Also, beware of vendors or re-sellers trying to put a competitor product in a lower position.
Longer answer: being 'tier 1', i.e., in your description, 1,000+ cameras, typically requires supporting the following features:
- Enterprise management
- Health management
- Deep third-party system integration (access, intrusion)
- Rules for triggering actions / responses
- Alarm / event management
- Network video wall
- Server / recorder redundancy or failover
- Video analytics and LPR integration
- Edge storage support
- Well documented API / SDK
- Sophistication / completeness of each of the above
- Actual track record of in-production large scale systems to verify that this all really works
As for Genetec / Milestone, Milestone tries a lot harder to win small to mid-size business than Genetec (in terms of pricing and packaging). So certainly Milestone is generally more appealing to small / medium than Genetec.
However, Milestone does have their own 'tier 1' type offering - Corporate which has pretty much all of those features. To that end, it is hard to say that Milestone is not 'tier 1', in your terminology. Whether Genetec is better or worse than Milestone is certainly more complex to answer and depends on one's needs.
If you were looking at systems that work at the 1,000+ level, I'd start by examining that list, what you need and what the VMS vendor actually delivers.