Some old British breweries use multiculture house yeast. Some have said Timothy Taylor does.
When I toured the Young's Ram Brewery a large open fermenter was shown. There were two yeast rings on the walls. The guide said the one up from the foam was from the fast starting yeast, higher up was from the workhorse strain, what we saw was the finisher that got the FG down.
PU had 5 strains, then selected two, now the have one.
I've thought of splitting a batch, fermenting each part, then blending. Of course I would taste each sample, and blend in a glass first to taste the blend. One might be really good, and the blend dumbed down.