Evangelion’s success in its second half despite its late night timeslot encouraged the production of experimental anime aimed at adults & aired on television.
Previously, experimental & adult anime were primarily the domain of OVAs (and this material proliferated during the OVA boom of the 1980s), but when the japanese economic miracle ended & the relative commercial failure of Akira gutted the industry of many of its established players, that material became harder to find; as a result, attempts to cash in on Evangelion’s success represented a kind of rennaissance.
Evangelion’s relatively successful merchandising (based in part on Gainax’s previous experience selling garage kits & working on video game tie-in properties) formed the basic framework for the modern adult-otaku-focused media mix plans that dominate the industry’s money-making apparatus: the focus on figures, home video releases, and merchandising based on the moe appeal of particular popular characters (something obvious in the fan communities Gainax grew out of, but not largely part of the planning of studios like Sunrise).
Certain things Evangelion did have not become industry standard. For instance, Gainax maintained the rights to Evangelion, rather than ceding it in perpetuity to the production committee. KyoAni does this, but most studios don’t, because they don’t have the clout to argue for perpetual rights for potentially-lucrative properties. Other practices Evangelion brought to the fore were actually common in the 70s and 80s properties that were Evangelion’s primary influences — like having a big, violent event movie as the ending to the series (something Ideon did with Ideon Be Invoked). Evangelion’s heavy and indiscriminate merchandising resembles nothing moreso than the merchandising of the first Star Wars film.