eHarmony's system only let you message people from a daily, "curated" list of matches. On any given day, you'd get 6 or 7 profiles on your email to review and decide to message or not. I'm sure you just did the math, 10% of 7 is less than one. Less than one viable connection a day.
Once I got past that "90% of these matches are dead ends" hurdle, it turned out about 50% of the people who were capable of replying actually did. I don't remember the exact breakdown, but basically there were a number of questionnaires you why through before getting through to love messages and asking people out. It was essentially a 50/50 filter at each step. IIRC, it was something like a half a percent chance that any profile eHarmony sent you would end up in an actual date.
I suppose dating sites figure, if someone finds their soul mate, they won't need to pay for a membership anymore, so don't actually match anyone, just strong them along for as long as possible.
for instance, to those who might say "she just didn't want to acknowledge you had matched," I saw it with my own eyes and also we were already involved with each other at the time.
FWIW, my perception is that this is not the case on Tinder, but obviously can't be sure.
Do you mind expanding as to how you were able to establish this?