>>Focus on Imaging had an attendance number of over 37,000 last year; however, CES 2011, which Canon attended (with a large booth) saw 140,000+ visitors.<<
2012 CES officially reported 153,000 attendees. To add - CES is covered extensively by major media in television, web, and print. Nikon, Canon, Fuji, Sony were all in Central Hall; with Nikon covering the floor with yellow brochure bags and Canon signage across the front pillars.
While Focus may attract a more industry-knowledgeable crowd, CES allows for market expansion and global visibility.
But there is one truth about trade shows. The expense to properly exhibit is very high - and it is hard to reason the return on investment. But exhibitors have to be there. So Canon not at Focus maybe a statement about Focus's impact more than about Canon's budget.