Not going to happen in the next 15 years, or even 50 years.
The USA probably has more trail 100s than any country on earth, likely more than the rest of the world combined. Judging from your Wasatch username you likely live in the USA and thus have a biased belief that trail 100s are big worldwide.
I do not know of any national/international governing bodies backing/recognizing any of the existing trail 100s.
USATF MUT does not support /recognize any trail 100's. I do not know of any trail 100s that are recognized as a national championship in another country.
Getting into the Olympics is sort of a political challenge, where you need worldwide participation, many governing bodies pushing for inclusion, and spectator interest. It also helps to have sponsorship interest.
There is not a lot of participation, let alone widespread participation in 75 counties, in trail 100s worldwide. You need widespread participation from places like Africa. Trail 100s are sort of a rich white man's sport, and you are not getting much participation by masses.
There is very little spectator interest.
There is not enough sponsorship $ backing a series of international events with prize money that could attract more worldwide participation, and perhaps spectator interest with sponsored TV coverage.
Do not compare trail 100s to any of the existing Oly sports, many of which were grandfathered in.