To be God's people and then to have that taken away and given to others was far worse than physical tribulation.
The nation was temporarily set aside as the LORD's agent upon the earth but she has not been cast away because at the end of the tenth chapter of Romans and the beginning of the eleventh chapter Paul states:
"But to Israel He saith, All day long I have stretched forth my hands unto a disobedient and gainsaying people. I say then, Hath God cast away his people? God forbid" (Ro.10:21; 11:1).
In this passage when Paul speaks of Israel it is obvious that it is Israel which is made up of the physical descendants of Jacob which is in view:
"All day long I have stretched forth my hands unto a disobedient and gainsaying people."
Paul is quoting from the OT so his reference to "Israel" at Romans 10:21 must be the Israel which had its beginning in the OT. Here is the verse which he quoted:
"I have stretched forth my hands all day to a disobedient and gainsaying people, to them that walked in a way that was not good, but after their sins. This is the people that provokes me continually in my presence; they offer sacrifices in gardens, and burn incense on bricks to devils, which exist not" (Isa.65:2-3; LXX).
So when Paul asks, "Hath God cast away His people" the words "His people" are referring back to the people of whom he just wrote about, the Israel he describes as being
"a disobedient and gainsaying people."
So when Paul asked,
"Hath God cast away His people" he was asking if the nation of Israel that had its beginning in the OT had been cast away.
And what he says next makes it plain that God has not cast away the Israel of the OT:
"God forbid."
At the time when the book of Romans was written Paul made it plain that Israel has not been cast away and what he says later makes that fact plain:
"Israel has experienced a hardening in part until the full number of the Gentiles has come in, and in this way all Israel will be saved. As it is written: 'The deliverer will come from Zion; he will turn godlessness away from Jacob. And this is my covenant with them when I take away their sins'" (Ro.11:25-27).