Keen for beer plumbing.

If we're piping allergens straight into people's homes, might as well have another one for peanut butter.

Just imagine the initial costs and maintenance costs of those pipes. It's already expensive routing water for people's houses. It's much less costly to do what was done in the past and have regular deliveries for those products in a reusable glass container and regular pickups of those containers. You also wouldn't really get a choice on the variant of the liquid you want like the type of beer, oil, or milk since everyone has their own preference or needs like with allergies.

Imagine if someone moves into a new house with a beer service line installed and they don't drink beer. The beer in that line would go bad and get really disgusting and probably contaminate beer in the rest of the line. The same goes for milk too. Imagine how disgusting a pipe filled with months old milk would be. Even ultra high temperature pasteurization won't save it. Imagine if you get a leak in your milk or beer pipe. Imagine if gets too cold or hot for the liquid and you get really warm beer out of the line or a slushy beer solution.

If you can guarantee those service lines will be used regularly, then I can see it being worth it since the maintenance costs and installation costs would be outweighed by the savings. Beer lines from a brewery to bars makes sense since the bars will be regularly going through a constant supply of beer. But on a regular consumer level, it's not worth it.

Tl;dr It's a logistical nightmare.

It's been proposed. Do a search for "soup tubes."