Every migrating cuisine arrives shorter than it started. Which dishes survive the move is not random, and the filter has more to do with logistics than with nostalgia.
Equipment is the first cut
Dishes built around a tandoor, a wet grinding stone or a wood fire cannot be reproduced faithfully in a standard American kitchen with a gas or electric range.
Approximations exist and are often good, but the gap changes the dish enough that cooks either accept a different version or stop making it.
Baking sheets and cast iron cover more ground than people expect, yet nothing in a home kitchen holds the sustained radiant heat that certain breads and roasts were designed around.
Time-bound dishes fall away next
Some cooking is inseparable from an hour of the day: a breakfast that must be griddled to order, a sweet eaten within minutes of frying, a snack that is only good at the moment it is assembled.
Those dishes survive where someone else is doing the cooking. Once every plate is made by a household member who also works elsewhere, they quietly leave the rotation.
What remains tends to be food that reheats, holds, or improves overnight, which is why the emigrant version of a cuisine skews toward stews and braises.
Ingredients that do not travel take dishes with them
A dish anchored to one variety of gourd, a specific green or a regional fish disappears when that item is unavailable, because substitutes change it past recognition.
Frozen and canned versions rescue some of this, and the produce sections of larger US Indian groceries have widened considerably. Seasonal freshness is the part that does not import.
Cooks adapt by swapping toward what a US supermarket carries reliably, which is how spinach, zucchini and cauliflower end up standing in for a longer original list.
Restaurants preserve a different subset than homes
Restaurant menus keep dishes that hold under heat lamps, portion cleanly and can be finished quickly from a prepared base.
Households keep dishes that feed several people from one pot and tolerate being made after a workday. The two lists overlap less than diners assume.
Between them, an entire middle category is lost: dishes that are neither service-friendly nor quick, which often includes the most technically interesting cooking a region has.
Recovery usually starts with one determined cook
Dishes come back when someone decides the effort is worth it and works out an American-kitchen route, usually involving a substituted ingredient and a rebuilt technique.
That version then spreads through family and community, and it is a genuine dish in its own right rather than a compromise, since every regional cuisine was built the same way.
The lost list is therefore not permanent. It is simply waiting on someone with a reason to rebuild it where they now live.