How can professional astronomers keep amateurs engaged given the ever-increasing power of modern telescopes? There're many amateur astronomers out there who build their own telescopes, write their own data-gathering programs, and scan the night sky tirelessly. Sometimes they even happen upon new discoveries simply because they had their telescopes pointed in the right direction at the right time.

However, the telescopes used by professional astronomers get more and more sophisticated all the time. This means that the window for amateur astronomers to contribute gets smaller and smaller all the time. For example, the recently-discovered Comet Borisov was discovered by an amateur, but the number of comets discovered by amateurs has been constantly decreasing. Which is obviously rather depressing. One day someone might write a poignant documentary which goes "I thought I was contributing, but then the professionals built [this telescope] and I've become redundant ..."

These citizen astronomers are obviously great PR for astronomy, but given the above, how can professional astronomers keep them engaged?
The role of amateurs in making discoveries will likely change. Telescopes like the LSST will make it even more unlikely that an amateur with a smaller telescope will detect an object first. But the LSST will produce a vast amount of data that will need to be processed, and amateurs may still play a role in this, as citizen scientists do with projects like Folding At Home.

Professional astronomers will continue the same outreach they currently do. Amateur astronomy is still rewarding without the vain hope of making new discoveries. It's enjoyable for the same reason people still visit scenic wilderness instead of just studying maps and photos of it on their computers.