—”You can’t maintain pressurize in gas lines in newer areas without over-pressurizing pipes that are leaking in older areas.”
My hundred-year-plus house had an almost as old underground gas pipes owned by the utility company.
Some years back a plastic liner was installed inside the main pipe and a new yellow plastic line was run to the house pulling with the old pipe.
One hole near the street and a small hole under the meter and pulled the new line from the house to the main for the connection.
It was a quick process.
I watched a junction replacement that took five weeks and involved a giant hole, traffic redirects, cops on site for the construction,etc. I couldn't imagine the cost and that was just for one junction, not even a major interchange.