Why 2 senior ministers and 2 DPMs?

There is an article in Zaobao forum on 8 Jul discussing why the PM needs two senior ministers and two DPMs to assist him. Given the super talent nature of all the ministers, surely the PM should be capable to hold the fort himself, alone. The forumer were trying to reason why is there a need for so many ministers to assist the PM. Subsequently he set this aside and commented on the impression of all the PMs, including the Chief Ministers that Singapore has had and found only David Marshall was the only one who could inspire and create a special aura around him. He then suggested that if the senior ministers were to volunteer to serve the country by taking a $1 salary, the people will greatly admire them for their greatness. After all every one of them have fortunes that could last several generations. Money is not an issue to them. Don't forget they are still receiving their great pensions, probably in the millions. This is an interesting article, really.