Agree with you that VictoriaMetrics works like a charm: fast, easy to configure, easy to recover from components crashes (last time I checked Cortex, it was a nightmare to recover from the ingestors). For me, it is the better solution for long term storage Prometheus if you come from a clean state.

But Grafana labs, employ lots of people that have worked on Cortex since its inception at weaveworks, and has developed strong in-house knowledge about it so Grafana is fully commited to Cortex (now Mimir) and have developed derivatives for logs (Loki) and traces (Tempo) heavily based on the Cortex model.