We see from Exodus 1 that Pharaoh wants to subdue the Hebrews, but he does not consider expelling them. Verse 10 says: “Come, let us deal shrewdly with them, otherwise they will multiply, and in the event of war, they will also join those who hate us, and fight against us and DEPART FROM THE LAND.” [emphasis added] Why did he not want them to “depart from the land? I speculate they brought value to Egypt that the Egyptians either did not have or did not care to develop.
The initial Hebrew, Joseph, had come to Egypt because his own brothers hated him and would have killed him or sold him into slavery. However, because of his character and work ethic he rose in Egypt to position and importance wherever he was; either as a servant or as a prisoner or as second in command to Pharaoh. He always did the best he could for whoever "owned" him. The “owners” prospered because of Joseph’s service; they liked what Joseph did for them. Because of Joseph in Pharaoh’s service Egypt not only was saved from famine but also prospered. Pharaoh brought Joseph’s family to Egypt and gave them land. All were content.
Apparently for a long time the Hebrews were no threat or irritation to the Egyptians because they not only stayed in the land but multiplied. The Egyptians were agreeable to this because the Hebrews were content to stay in the land. There was nothing reported in the Bible about any Hebrew discontent or rebellion. I would guess the Egyptians enjoyed the food stuffs, crafts, and skills the Hebrews brought with them.
Eventually a Pharaoh that “did not know Joseph” (see verse 8) becomes worried about the Hebrews because of their sheer numbers. Ignoring that the Hebrews had been among them for a great while he worries they will side with an enemy in the event of a war. He ignores that they had apparently never showed any signs of discontent or rebellion. He decides to put them under hard tasking; in other words, they became slaves. Even though the Hebrews are oppressed they still do not rebel or leave. I am curious why the Pharoah did not think this drastic change in Egyptian attitude would not make the Hebrews favorable to leaving
And that, under Moses and through God’s help, is just what they did.