To my mind Larger and Indian pale ale both are designed to be stored, to make a Larger the yeast has to work at a low temperature, and everything has to be really clean, it takes longer to produce the alcohol, so more chance in early days of getting some thing in the brew before the alcohol preserves it.
However once made it should last for years.
But although both IPA and Larger tend to be light coloured, there is no reason why a Larger should not be dark, but because it takes so much longer to make, it means you need a lot more storage. So personally can't see the point, I can make a standard brewed beer which tastes the same as Larger in 1/4 of the time, and taking up 1/4 of the space to store.
I Europe there was a problem with heat in the summer, UK was a lot cooler, so the Larger was made so brewing could stop in the summer months, and there was a reserve to fill the gap between stopping brewing and restarting again, but they likely proper beer that much they had a festival to celebrate the first of the proper brews.
Same with IPA is was designed to be shipped to India, it had to stand the heat and the shaking of travel, it was to hot to brew in India.
Today with refrigeration there is no real reason for either, and the names have come to mean light ale, and associated with a taste, and you can buy a "Larger Kit" but it is not really Larger, it is brewed at 20 deg C as with a kit we use tap water not boiled so if we try to Larger it would go off before it had made enough alcohol to stop unwanted bacteria, and read the label on a tin of larger and it is clearly not intended to be stored for years any more, it has same life as any other beer, one questions if really a Larger, could commercial brewers really afford the space to store Larger for such a long time?
Idea is good, slow brewing with constant output, and a store that absorbs the fluctuating demand, but today the Toyota idea is used everywhere, the just in time, so nothing is stored any more.