The reason for Early Access this time is financial, not Larian's good experiences. Larian has to release the game in some form by the end of 2020 because Hasbro wouldn't want BG3 to take up mindspace and marketing hype for their intended release of one D&D game per year through 2025.
Dark Alliance will be this year's DND game, BG3 will be the one for 21.