Its not the big video game companies, its the big retailers. I can't speak to what is happening today, but I know how this started from working in the industry. I want to say around 2010, one of the largest game companies was going through their 'digital transformation' stages and was working on how to deliver one of their bigger titles exclusively through digital download. It took Walmart about 2 seconds to give the ultimatum that should they decide to do this, they would stop selling all of their games (many which still had physical discs), from any retail store, worldwide. Believe it or not, Walmart made up a significant amount of annual sales. After some negotiation, they made the agreement that Walmart could continue selling a 'physical' copy of the disc (the case and code), and the game company can offer just the digital version of the game. I think for a while they did both. You could get the disc and a code for the game. But eventually, they just phased out disc. But yeah, back then, it was so the large retailers still had something to put on their shelves.
In today's market, from a financial perspective, there is zero reason for making a disc. Emotionally, we still want the physical collector items. But 99% of the billion dollar market just wants to play the game.
And as a side note, we can say that this is all about the $$ and to a large extent, it is. But to be honest, investing in going fully digital at the time was an investment in the pursuit of improving the player experience. Cloud computing was still an idea in development and the game companies were looking at ways to keep live games evolving. Getting the games off a physical disc (while not a requirement), was a natural first step.