To be fair, they did address this concern under the 'Operating Leverage in Our Business' section where they said that they may look for another third party to rely on for cloud computing or they build their own infrastructure.
"We have committed to spend $2 billion with Google Cloud over the next five years and have built our software and computer systems to use computing, storage capabilities, bandwidth, and other services provided by Google Cloud, some of which do not have an alternative in the market. We are currently negotiating an agreement with another cloud provider for redundant infrastructure support of our business operations. In the future, we may invest in building our own infrastructure to better serve our customers."
"We have committed to spend $2 billion with Google Cloud over the next five years and have built our software and computer systems to use computing, storage capabilities, bandwidth, and other services provided by Google Cloud, some of which do not have an alternative in the market. We are currently negotiating an agreement with another cloud provider for redundant infrastructure support of our business operations. In the future, we may invest in building our own infrastructure to better serve our customers."