Is it necessary for us to perform five daily prayers, leaving work which is necessary for our food?

Praise be to Allah, the Lord of the Worlds; and blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
Allah created man to worship Him Alone. Allah has prescribed to everybody their fate and what they will have in this life (their sustenance and nourishment). This sustenance and nourishment does not expand neither does it diminish.
In fact the person does not die before consuming all that was prescribed to him. Evidences for this are numerous in the Qur'an and the Sunnah. Allah Says (interpretation of meaning): {And I (Allâh) created not the jinns and humans except they should worship Me (Alone). I seek not any provision from them (i.e. provision for themselves or for My creatures) nor do I ask that they should feed Me (i.e. feed themselves or My creatures). Verily, Allâh is the All-Provider, Owner of Power, the Most Strong.}[51:56-58].
Abdullah said: "Allah's Apostle, the true and truly inspired said, "(as regards your creation), every one of you is collected in the womb of his mother for the first forty days, and then he becomes a clot for an other forty days, and then a piece of flesh for an other forty days. Then Allah sends an angel to write four words: He writes his deeds, time of his death, means of his livelihood, and whether he will be wretched or blessed (in religion). Then the soul is breathed into his body. So a man may do deeds characteristic of the people of the (Hell) Fire, so much so that there is only the distance of a cubit between him and it, and then what has been written (by the angel) surpasses, and so he starts doing deeds characteristic of the people of Paradise and enters Paradise. Similarly, a person may do deeds characteristic of the people of Paradise, so much so that there is only the distance of a cubit between him and it, and then what has been written (by the angel) surpasses, and he starts doing deeds of the people of the (Hell) Fire and enters the (Hell) Fire."
Ibn Majah reported that the Prophet said: "O people! Fear Allah and be moderate when you ask to have something. Know that nobody will die before consuming completely what was prescribed to him even if he gets it late. So fear Allah and be moderate when asking to have something. Take that which is lawful and leave that which is unlawful".
Know also that the five prayers which Allah made mandatory on us during the day and the night are among the most important obligations. In fact the prayer is the second most important pillar of Islam after Shahada bearing witness that none deserves to be worshipped but Allah and that Muhammad (Peace and blessing be upon him) is His messenger. It is the prayers after the Shahada that bring one closer to Allah. So, the prayer has a great place in the Muslim's life.
So, it must observed in its fixed times with all its conditions, obligations and Sunan. Doing so, brings happiness in this life and the Here after.
On the other hand, there is no contradiction between performing the prayers in their fixed times and seeking profit and earnings to be obtained in the legal way with what Allah has ordered.
Indeed, the fixed times of the prayers, conform with what is good for the human beings because it is The All-Knower, The Compassionate Who has set them. Allah has made these times appropriate with the well being of His servants. Also, performing these prayers takes but a little time. It should be obvious to you that no matter how hard the person works, he will get only what Allah has prescribed for him.
Allah knows best.