> instead of just integrating it into mobile broadband networks
Because mobile networks are oversubscribed. They're simply not designed to support everyone using them heavily at the same time - it's why folks are advised to stay off cell phones during emergencies, or fail to be able to connect if they do use them.
Much like other ISPs, there's little incentive for mobile providers to build out to properly support their customers when it works most of the time even when oversubscribed.
Because mobile networks are oversubscribed. They're simply not designed to support everyone using them heavily at the same time - it's why folks are advised to stay off cell phones during emergencies, or fail to be able to connect if they do use them.
Much like other ISPs, there's little incentive for mobile providers to build out to properly support their customers when it works most of the time even when oversubscribed.