Why do you still need to buy games on Stadia?

Today Google released the price and the release date for its gaming platform, Stadia. According to the release, no matter which version of Stadia you choose, you will still need to pay a significant proportion of games on the platform (for Stadia Pro subscribers, they have free access to some games; for Stadia Base users, they have to pay all the games). Some people are comparing Stadia with Netflix and say Stadia is the gaming version of Netflix. In some ways, they are correct. By using Stadia, people no longer need to download the games they want to play, worry about their hardware, they can immediately start playing the games whenever they want to play, just like people watching films on Netflix. However, even if people subscribe the Pro version which will cost $9.99 per month (to be honest, this is relatively cheap, especially after Apple announcing its $1000 monitor stand), why will they still need to pay for the games? Why doesn't Google offer free games to its Pro subscribers, though the Pro subscribers will get some discounts when they purchase some certain games?

In my opinion, this may be caused by two side factors. For Google, if they offer free access to all games for its Pro subscribers, they have to pay for the game providers. Some games are very expensive, since the production costs are high; Google doubts if it can collect enough profits to pay for the game providers to make them continue providing games and attract more game developers. For game developers, receiving payment from Google may not be ideal. At this moment, game providers are uncertain about how much Google is able and willing to pay. Although this might increase the quantity, this would reduce the margin significantly, which may not be able to be compensated by the boosted quantity. The strategy that Google chooses at this moment may indicate that both Google and the game providers are not so confident. I think if Google totally believed its gaming platform, Stadia, would succeed, Google would increase the subscription fees for the Pro version much above the current level (maybe $35 or even higher), guaranteed some certain payment levels for its game providers (which means if the game providers' revenues received are below the guaranteed level, they will receive compensations from Google).

At this moment, I am very excited about Google releasing Stadia. I am not excited about the games I can get instant access to games, I am excited because I can see that in the future, people will work on the cloud and no longer need to depend on the hardware they have. People can get access to a simple Windows desktop and use Microsoft Office on a Huawei smartphone (maybe other smartphones also have a similar feature, but I personally only use this feature on a Huawei smartphone); in  the future, people may be able to do any kind of work via any kind of console they have access to. I am looking forward to seeing this future coming.