It's a good question and I believe there are a number of factors, so it's not easy to single one.
A few that stand out:
Over the last 15 years, there are at least 3 core areas of focus:
- Software Only
- VMS + Analytics
Regardless of how good one executes, going after the VMS + analytics market has been very hard simply because analytics acceptance has been weak (e.g., 3VR and Aimetis, even Cerinum, who did a recorder first and VideoIQ who tried to be a recorder). If you are pinning your VMS on analytics, you are going to struggle.
Amongst the rest, a key strategic differentiator was whether a VMS company choose to focus on software only or appliances. For example, Exacq succeeded against more established players like Genetec, Milestone and OnSSI by having a fully developed line of appliances, something that these companies are still trying to match today.
Software Only Competition
Lots of VMSes focused on software only. The key to success here is controlling the high end of the market where advanced software features really count and the motivation to use low end appliances is minimal. This is why Genetec and Milestone have been so 'successful' because they have a ton of features that makes a difference to bigger buyers.
To me, that's the big challenge for the 'others' in the space - the Texans (Video Insight, Salient, Lensec), ipConfigure, Luxriot, etc. It's hard for them to beat the big 2.5 (Genetec/Milestone/OnSSI) because of their feature advantages.
Starting Early / Experience
Another key factor is time / experience. Both Milestone and Genetec started in the 1990s which is a big advantage both for developing features and learning the market. Exacq's core team learned from doing Integral and selling that to Pelco.
For example, people at 3VR were incredibly smart but none of us had the depth of market understanding / expertise in the mid 2000s that I am sure Exacq / Milestone / Genetec already had.
I am not saying experience / early starts determine success (see JDS and what happened to them) but it certainly helps a great deal.
Look, there has only been one pure play new entrant to the Western VMS market in years (Network Optix). I think that reflects how mature the products are and how challenging it is to develop the breadth of features to compete.