Where do you get that number from? Did we land 25 moon probes before sending Aldrin, Armstrong, and Collins?
The moon is 250 thousand miles from Earth. Mars is 9.3 Million miles from Earth. It makes a difference.
Logistical differences required by the huge difference distance traveled mean that at the moment a manned mission to Mars is not with in the abilities of NASA.
The Apollo missions to the Moon took 3 days.
It is estimated that a manned mission to Mars will take 6 months at minimum one way.
Once an engine is developed that can push a spacecraft from the Earth to Mars in a week or a month a Mars mission will make logical sense.
Have a good long look at the number of space flights that were done prior to the lunar landing. I'm talking Mercury, Gemini and Apollo. Also note that we had not one, but TWO Apollo missions that only served only to demonstrate that we could reliably get to the moon and back before we even attempted a landing.
All of that preparation was done so we could cross roughly 500,000 miles of space (round trip).
With a Mars mission, we are talking about several orders of magnitude more complexity in terms of planning and mission execution. Even in optimal conditions, the one-way trip to Mars over 140 million miles. A round-trip journey would also require an extended stay on Mars until Earth and Mars again approach perihelion distance (an aphelion departure from Mars would add another 26 million miles to the journey).
And you think we shouldn't set a bar on how many successful consecutive unmanned missions we should have before sending people out there?