I think there are ways to use a single pipeline for multiple kinds of loads (in serial), but yeah a bunch of new pipelines would be needed to get the loads to a bunch of new places.

"single pipeline for multiple kinds of loads (in serial)" <--recipe for pipeline explosion.

Who wants a pipeline behind their home that transports chlorine gas one hour and ethylene gas the next?

Like this one ?

https://channelnz.com/what-we-do/terminal-pipeline-services

Not sure how dangerous it would be though to have one transport wildly different chemicals...