Maya my little Mac produced 100-150 apples last year, and this year around 20.
I have a smaller Mac Free planted 20' away and it has yet to produce. I had to replace a Fuji that died of the FB and went with the Mac Free.
Perhaps next year they will both kick in and I will be canning or freezing some apples. We'll see.
Make sure you thin them every year, especially when it looks like a bumper crop. You want one apple every 5-6 inches if possible. It takes a year for a bud to form an blossom, so if everything is fruited, nothing is developing for the following year..... Properly spaced Liberty apples.