So your claim is that Datadogs pricing is ridiculous and that Otel allows you to not be locked in, but somehow Otel isn't a thread to Datadog? I don't follow.
In theory you could use the Otel Collector (or any other Otel-compatible agent) instead of the DD Agent to collect metrics/logs/traces. This would then make it easier for you to switch from DD to another Otel-compatible provider (Grafana, for example)... but 99.9% of what DD provides is _not_ the agent, it's dashboarding, alerting, RUM, synthetics, etc.
Basically Otel has made _agent_ switching costs effectively drop to zero, but that is a very small part of the whole picture. Like I said above, this primarily hurts vendors with proprietary agents that can't/won't adopt Otel for ingesting data.