I think Bike MD dropped TdP this year. If I'm remembering correctly, they offered a different route called the Urban Adventure and a week before that ride, they canceled it as well.

Bike MD is going through a lot of changes right now.

Not sure if it's a common issue, but it seems like the ridership on big supported events has definitely fallen off in the last couple years. The organizations often have differing excuses for cancelling, but it's a trend.

Eat a Peach also canceled this year.