I kinda agree that they are different industries, but I do think the parallels between the movies and games are very strong nowadays, now that both have become mainstream. I think it's acceptable to say that they're not necessarily identical and don't work in the exact same way, but there's a strong indicator that they resemble each other in the fact that game publishers also seem to think the same way about AAA/blockbuster sequels - in short, that it is a good investment to continue to do more of the same.
Sounds like a
"go big or go home" scenario. Looking superficially at the data of the biggest game franchises (and accepting
wikipedia numbers without further investigation, which I agree is not necessarily reliable), the results seem quite inconsistent: franchises like GTA, Witcher, Pokémon, The Elder Scrolls, Call of Duty, Borderlands and others don't seem to follow any simple pattern that I can notice, with numbers all over the place. Many of the sequels appear as bigger success than the predecessor games, but franchises with many games have also very big fluctuations on sales. Many sequels were also released many years later, which obviously changes the whole scenario and number of gamers / possible buyers. Anyway, the only consistent thing is that you only really see several sequels in "big" games/names, which is quite analogous to what we see in the cinema. Whether it's movies or games, either you invest tens or hundreds of millions, or don't think about franchises/sequels at all.
Which in essence I think is the argument VD is making: for indie groups and small or medium sized games, and perhaps especially RPGs, success cases of sequels are exceptions. Divinity: Original Sin 2 seems to be one of the few, but at the same time it is also one of the games with the highest production values of recent RPGs, which makes it a game closer to AAA group than to indie group.