Over the last few years, lots of renewable generation and storage projects have taken advantage of the grid capacity in this area, but all the low hanging fruit is gone now.
These days, it is not usual for projects to be given a connection date in the 2030s due to the requirement to reinforce the transmission network.
The CEGB constructed the 400 kV supergrid in the space of 15 years during the 60s and 70s. A project of such magnitude today would most likely be tied up in the planning consent process for 10+ years.
It really happened gradually, though, and with much less surrounding complexity. To give an analogy, OSes developed really fast, but any significant change in the kernel now will require lots of caution and scrutiny.
Also huge advances can have lots of things not "solved" - the first vehicles sucked majorly and were finicky as all get out, but compared to a horse-drawn cart they were so amazing as to excuse all the failings.
Modern cars are so good that any advancement is going to be incremental, and so it will take longer.
And early in electrification the whole local grid going down for awhile because who knows why wasn't a major issue, it was almost expected.
Some towns didn't even have power until near nightfall as a planned runtime; why bother with power during the day?
Now we're used to 100% always-available power at all times, and the demands on it are growing. Things like power walls may become nearly free as the grid maintainers try to flatten demand so they can run the grid closer to capacity for longer each day.
Over the last few years, lots of renewable generation and storage projects have taken advantage of the grid capacity in this area, but all the low hanging fruit is gone now.
These days, it is not usual for projects to be given a connection date in the 2030s due to the requirement to reinforce the transmission network.