Rather than spiritualize the 144,000 Jews into all people, you might consider that they do indeed refer to Jews who had be scattered among all nations during the time of great tribulation and who now will be returning to their land.Revelation 7:9
“After this I beheld, and, lo, a great multitude, which no man could number, of all nations, and kindreds, and people, and tongues, stood before the throne, and before the Lamb, clothed with white robes, and palms in their hands;”
After the sealing of the 144,000 John clearly tells us how many and where these elect, spiritual Jews came from....lo, a great multitude, which no man could number, of all nations, and kindreds, and people.
The fact that each of the 12 tribes is mentioned and the number of each, gives credence to the fact they are indeed Jews.