You're arguing with a truism, that things that are the same cannot be different!
Of course that's true. But I'm trying to argue that the categories created by Dispensationalism separate things into different compartments when some of those compartments are not different at all. So Dispensationalism is saying some things are different when they are not. The differences that I do acknowledge are not confined by the "dispensations" that Dispensationalism says should confine them.
For example, I acknowledge the difference between the Church and Israel. One is an international group, whereas the other is strictly a national group. I also acknowledge the difference between national Israel being presently under a curse while the nations that represent Christianity today are under a blessing.
These differences do not fit neatly into dispensations including 1) the NT age up until the 7 years of Antichrist, 2) the 7 years of Antichrist, and 3) the Millennium. All 3 "dispensations" include Israel and the Church. The entire NT age is characterized by nations that rise and fall, including Israel and the Christian nations. The fall of Israel, as a nation, therefore, does not preclude it from being included in the NT age up until the reign of Antichrist!
As a side note, I do not believe the reign of Antichrist is a 7 year period. It is strictly a 3.5 year period. Nor do I think the period of Antichrist's reign is the 70th Week of Dan 9. That Week was concluded with the death of Christ and the end of OT offering.
To punctuate and to emphasize this conclusion of the 70 Weeks of Daniel, we were told the city of Jerusalem and the OT temple would fall. This was the "Abomination of Desolation," the Roman Army that destroyed Jerusalem 70-135 AD, leading to the age-long Great Tribulation of the Jewish People.
It consisted of the loss of a homeland for the Jewish People, as well as a rejection of the Christians among them. The Church can learn from this in their own post-Christian nations!
To reiterate, I acknowledge that these are legitimate categories of time, and can be expressed as "dispensations." They are the NT age up until the reign of Antichrist, the reign of Antichrist, and the Millennium. However, as Dispensationalism defines them, they do not express separate realities outside of the fact they are different time periods. As such, we should not express them as "dispensations," because that is misleading.