Sure not everyone is always going to be using it at the same time, but streaming times are going to be around the same because most people will clock off at around the same time, and new technology such as Google Stadia, the introduction of 4k streaming, etc. mean that it's very likely that people will start needing more bandwidth soon, no?

Also the target audience of this, the people that will be able to afford it, are going to be highly paid people (assumption: it's going be charged higher than 30£/month, or even £60/mo) who will be more likely to do those sorts of activities due to having more free time.