The distribution firms are not charities
Installing a new electricity transmission line costs multiple millions (and takes years to complete - in part because of the need for planning permission and the need to purchase land rights). For the companies (National Grid and others) to make such an investment, they need to be reasonably certain that they will make a profit from doing so. The firms are not charities. For any new line the end users will be paying for it in one way or another - a small proportion of the price of electricity covers the cost of construction and operation of transmission lines. If the predicted demand is insufficient to cover the costs of the transmission lines then it will not be built unless the end user(s) provide part of the funding.
Icon for the people who find that they can not charge their government mandated electric vehicles due to no power being available =========>