Ever since 2014 when O3B started being installed on RCI ships, two tiers were introduced and throttled. Like now with some Starlink installs, those speeds varied during the testing phase (some early O3B installs had 25Mbps down speeds). Eventually, both offerings settled on the current limit of .5 Mbps for Surf and 4 Mbps for Stream. Most reporting suggests those same limits will continue with Starlink and there's no indication they would be increased.
The thing that changed over the three types of internet offerings is the latency, from a best of about 600ms on legacy installs, to 200ms with O3B and now maybe as low as 50ms with Starlink. It's that low latency that will allow most folks to perceive a performance improvement even if the speeds are kept at the old limits.