The importance of Salaah

Q: I saw the following two hadith:

Our Nabi (Sallallaahu Alayhi wa-Sallam) said: "Do not forgo Salaah intentionally, lest you should get out of the fold of Islam. Do not perpetrate disobedience to Allah, lest you deserve His Wrath."

Rasulullah (Sallallaahu 'alayhi wa-Sallam) also said: "The dividing line between kufr and Imaan is Salaah." And : "A person who has missed one Salaah is like one who has lost all his family and wealth."

1. A person who misses salaah in its time but reads it later does he lose his imaan?
2. Is he still a muslim?

Q: We are taught that at the time of salaah we should close our businesses and proceed to the musjid. What about those businesses that are extremely huge and require a lot of time to clear the customers out e.g. wholesalers, major supermarkets, factories, etc? Is it permissible for these businesses to remain open?