In its heyday Earth was a great interplanetary trading post on account of its low gravity moon which was used as a warehouse for all kinds of goods.
The Moon was covered almost entirely in large warehouses and each had a staff of thousands. These people were manual workers, management and administrators plus technicians to maintain living conditions. All the people you would expect for a large business. None of them were research scientists although there were a few engineers.
Sadly Earth was hit by an asteroid causing extinction of all non-aquatic animal life. Many edible plants and sea-creatures survived.
Even more sadly, this coincided with a slump in the galactic economy. Trade died and no-one came their way any more - not even pirates who have no access to FTL travel.
Can they ever escape from the Moon back to Earth?
They have whatever minerals etc. already exist on the Moon (as known in 2018).
They have their buildings and equipment which are made of 2018-level technology and materials.
They have a vast quantity of goods in the warehouses.
These goods consist of (and only of) anything that could be bought on Amazon in 2018. But they don't have to buy it - it's already in their warehouses.
They have all home comforts for family life including fresh fruit and vegetables grown locally.
There are no petroleum deposits on the Moon as life had never existed there before the advent of humans.
They don't have any kind of space ship. They relied entirely on a now defunct shuttle service to get from Earth and back assuming they wanted to.
There was limited farming of animals because of the difficulty in growing sufficient quantities of foodstuffs. Meat is a luxury and most pets were banned as a consequence.
So - can they ever escape from the Moon to Earth and land safely? If not can they survive indefinitely on the Moon as a community?