There have already been tests of Illuminations cruises using a friendship boat (the ones that ferry you from Epcot to MGM and resorts between). I can't imagine how half the boat actually saw anything, but rumor has it that the Epcot brass was happy with the results. The revenue stream on a per-seat basis is probably better than selling the pontoon boat rides individually for groups of up to 12.
If this does happen, there may still be pontoon boats for Illuminations. If there are, there will be fewer available than there are today.
If this does happen, there may still be pontoon boats for Illuminations. If there are, there will be fewer available than there are today.