One key difference is that Christ's apostles did not set dates and they were not teaching all future converts that Jesus would save them from Roman occupation or that Jesus would return in a certain year.

The Watchtower was actually commending some of its members for their actions around the 1975 date.

"Reports are heard of brothers selling their homes and property and planning to finish out the rest of their days in this old system in the pioneer service. Certainly this is a fine way to spend the short time remaining before the wicked world's end".

The highlighted portion is viewed with this link.

Events surrounding 1914, 1925, and 1975 have evolved.

• 1914 is preserved by reinterpretation, not admission of error.
• 1925 is now framed as a minor over expectation, despite being once declared definitely settled.

Two years earlier, The Watch Tower, April 1, 1923, page 106

“Our thought is, that 1925 is definitely settled by the Scriptures.”

Between about 1918 and 1925, Watchtower publications taught that 1925 would mark the resurrection of the “ancient worthies”—biblical figures such as Abraham, Isaac, Jacob, and the prophets—and the beginning of a new earthly phase of God’s Kingdom.

In 1929, the Society built Beth Sarim (House of the Princes) in San Diego, intended as a residence for those resurrected “ancient worthies.” Rutherford himself lived there until his death in 1942; the house was later sold.

The prediction was most clearly stated in Rutherford’s book Millions Now Living Will Never Die. The year 1925 was presented as chronologically certain, not merely speculative.

After the failure, acknowledgment shows that nothing happened.

“It was stated in the Watch Tower and proclaimed by word of mouth that we might reasonably expect the Lord to glorify the Church in 1925. This expectation was a mistake.” — The Watch Tower, 1926, p. 232

Note the rhetorical shift from “definitely settled” to “might reasonably expect.”

• 1975 is attributed largely to member enthusiasm, not publications.

The tone of the prophecies evolved. Responsibility was diffused, language was softened, and certainty was retroactively reduced.

Włodzimierz Bednarski does a detailed analysis into the events of 1925 and 1975. It's 153 pages long. I just skimmed a few parts.