Friend cannot commit to an apt! Ever!

I guess the obvious is she is not into the activity, but why not say so? 25 years been friends, I suggest anything and she is so keen, until the day then OMG the excuses! Gotten to the point I will not answer ph that day from her. So just in last 2 years; Fallen off bike - 6 times. Unwell, pretty much twice a month. Think the dogs been bitten by a snake - dog fine no snake sighted. Bushfires - completely out 8 hours prior to activity. I have to work, fair enough. When she commits to an activity she is always late, forgets the cash, It never goes smoothly! How should I approach? We have tried movies, No lights no Lycra, Salsa and Zumba & meditation class. We got to some once and got to point I go alone as so unreliable.