Famous last words. A better design is to assume leaks occur, and design to minimize the damage. (This is how airliners are designed.)
> with automatic block valves
That's compartmentalization, not elimination.
Another method is to use two smaller pipes instead of one larger one - it reduces the scale of any leak.
Elimination of the hazards is impractical, so minimization of risk exposure and frequency is the best that can practically be done.
All the hubbub about stopping new pipeline construction means that more incident prone methods are used - be it trucking, rail transportation, or use of 50+ year old pipelines. The new lines are better engineered, understood, and have more stringent operational controls in place. I've worked on pipelines from the 1940's that are still safely operated, and lines from the 2010's that have already self excavated. These things can be controlled with the right engineering, organizational, and governmental oversight.
As to other transport methods being less safe that also comes down to building safe systems. Car gas tanks for example are designed to survive crashes without spilling their contents. You can also build tanker trucks/trains to appropriate standards.
use two smaller pipes instead of one larger one - it reduces the scale of any leak.
And cost isn't linear either, two half-capacity pipes will probably be almost twice the price. You could spend that on more steel for the large pipe instead.