Here's Rav Avigdor Miller, who refused to align with the Zionist movement (out of love for Hashem, Torah principles & Am Yisrael), held a purely religious view on Eretz Yisrael & stated:
We have a claim to Eretz Yisroel and it’s written black on white.
We have a charter.
The Torah states openly it belongs to us.
It was given to us and we lived there.
The fact that we were driven out at gunpoint, at knifepoint, doesn’t mean we lost the rights to be there.
TAPE # 482 (December 1983)
1) This is the MAIN and MOST IMPORTANT reason:
UPDATE 2020: The Lubavitcher Rebbe stated that we have no right to give up Land that does not belong to us; it belongs to HASHEM:
The Lubavitcher Rebbe: Israel is Not Yours to Give Away
We are halachically forbidden from giving Land to those to whom it doesn't belong, particularly to people who despise us and want us dead. Therefore, giving away Land brings harm, not blessing. And needless to say, any reasons stated by Chazal permitting us to give up Land do not in any way apply to the situation we've been in for decades now.
If anything, the whole episode with Bnot Tzelafchad, as mentioned in the recent parshas, bring this point home.
2) We've already given up too much. Jordan, Syria, Lebanon, and teeny bit of Turkey (just to name a few) are all squatting on Land that Hashem designated for Jews and command us to settle.
So which nation(s) REALLY need to compromise?
That's right! NOT us.
(Okay, and yes I know that exact boundaries are disputed by Chazal, and that Reuven, Gad, and Menashe II are outside of Eretz Yisrael proper, etc.)
Below are photos of our Tribal Lands. Keep scrolling and enjoy the view!
Reuven/Reuben

Shimon/Simon
Levi (The Levites did not receive a standard Tribal portion, but served in the Beit Hamikdash and lived in the Cities of Refuge)
Yehudah/Judah
Yissachar/Issachar

Zevulun/Zebulun
Binyamin/Benjamin
Dan
Naphtali
Gad
Asher
Ephraim
Menashe/Manasseh
May all of Bnei Yisrael be gathered into Eretz Yisrael very soon!