A moat can be a strong and established brand like Coca-Cola or, if we take in marketplaces, AirBnB with their network effects.
When it comes to a white-label SaaS (for example, a simple accounting software) - how should we think about building and growing a moat?
I run a few small SaaSes, and I try to reply customer email within 24 hours, and usually they are suprised / delighted by my response, and most stayed, or switched away from bigger competitor to mine, after initial enquiry to my app.
The moat is more likely the company that is being white-labelled, as the others cannot exist without it. So I would posit that any white-label SaaS has no possibility to have a moat. It will never reach the level where it matters, and by definition, their product is easily reproducible by another getting the same white-label deal.
My understanding of Buffet's strategy is that he invests in supply chain choke points and brands that people love and are likely never to go away, not "moats". He also doesn't really do tech investments afaik