Possibly the strongest reason to expect some hardware announcement is the age of the 16" Pro. Given it's probably realistically their flagship Mac (80% of Mac sales are notebook form factor, and the Mac Pro is niche expensive) it's already gone a surprisingly long time between updates, the longest ever as far as I can see for the 15/16". As the next opportunity to launch may well be October, do they really want to let this important model sit untouched for 23 months? They've of course gone that long and longer for other Mac models, but those were comparatively niche models, and/or limited by chip availability, or had their whole future in doubt...