Not quite. Almost everyone who is 75 today (well, the 97%) got married
at some point. That doesn't mean that people 25 today will get married
by the time they are 75.
I have several older gay friends, men in their 60s, who got married
because it was the thing to do in the 1950s. (Well, either that or
they became priests.) Many of them would not get married today if they
had the same choice.
The numbers don't just reflect marriage by age, they're convoluted
with marriage by decade.