Not to pile on, but I also suspect that outsourcing might be a potential factor for the differential. Jurassic World is the current era of films and Universal pushes it very hard, we have seen them covering up and pushing Jurassic Park to the sidelines or limited time events. Makes sense from a marketing standpoint you want to push product that aligns with your present business, but I do find it sad we are seeing what amounts to a slow erasure of Jurassic Park. Sure, there are lots of easter eggs and some occasionally neat stuff, but overall I am seeing the tropical vibe being supplanted by the clean, sterile Jurassic World aesthetic.
Speaking of Frontier they are likely just aligning with Universal's agenda and put more resources into the Jurassic World sections of the game, Jurassic Park is there but not as well represented. I also think its a matter of just general allocation, a lot went into the dinosaurs as it rightfully should have which explains why there are fewer new species but could also explain why less work was done for other aspects of the game. I just wish Frontier would just come out and say they'd patch these in later so at least the era parity can be achieved.
Lagoons we have an argument didn't exist in Jurassic Park, but it can't be that hard to create an era equivalent for them, there is an established aesthetic they are already using for this era that just needs to be tossed on the Lagoon. If they went the extra mile to distinguish it, even better.