The Watch Tower Society taught until 1935 that the "Great Crowd" was a second class of Christians with a heavenly hope.
The 144 000 were the Bride-class, the Great Multitude (Crowd) an attendant class ('Brides-maids').
The increasing numbers of Bible Students affiliated with the Watch Tower Society did not force the change in doctrine. The teaching allowed for large numbers of heaven-bound Christians. The Watch Tower Society taught the following in the 1917 publication The Finished Mystery on page 103:
FM103
Was ten thousand times ten thousand, and
thousands of thousands
.— The number of theGreat Company will apparently exceed one
hundred millions. Num. 4:46-48 and Ex. 28:1
indicate but one priest to each 2,860 Levites,
which would make the number of the Great
Company approximate 411,840,000.— T118,
119; Dan. 7:10. 5:12
Currently, belief that more than 144 000 will receive a heavenly reward will result in Disfellowshipping. (w 01. April 1986 QfR)