Do the Invisalign Attachments Stay on for the Entire Treatment?

Normally, they stay on during the entire treatment.  It is possible that they can be taken off early, but it is best to design this into the case at the beginning.  If not, the aligners at the end of treatment may be designed to USE the buttons, and without them the movement may be unpredictable.

While you certainly can tell they are there, it is possible that others won't or can't notice.

Yes, they do.   Should you finish one arch before the other; the attachments can be removed on the completed arch.

Attachments for Invisalign usually stay on for the duration of treatment.  However, sometimes they can be added part way into treatment or taken off before the end of treatment.  Attachments are used more than they used to be a few years back allowing better control of the teeth and therefore resulting in a more predictable and better result.  Having them on the front teeth (if upper) usually means they require special needs such as moving the roots back more (called torque) or closing an open bite.  None the less, I appreciate your disappointment in having so many attachments, but would recommend talking with your Invisalign provider, then following the recommendation to get your best result.  Good luck!