They are in self-serving denial
Pretty simple, really. The average storage shipped with a laptop increases over time because the smallest laptop drive is always getting bigger, and the cost penalty from one platter one head to two platters four heads is pretty minimal, so its a cheap way for vendors to make the laptops seem better when naive consumers are comparing them against each other.
Most people don't come close to filling up their laptops. Corporate laptops mainly use data on corporate servers, without a need for lots of local storage. A 32GB drive is probably plenty for most of those, with hard drives offered by corporate IT on an exception basis only. 32GB is probably fine for most consumers as well....maybe a bit larger to capture 90-95% of the market. For the rest, who are mainly DV enthusiasts or download/rip lots of video, spinning media will remain the way to go.
I would anticipate in the next couple years some changes in the laptop market. SSD vendors will probably come up with a standardized small form factor SSD - probably about the size of a mini-PCI card. Then laptop vendors will ship the bulk of their models without space for an internal hard drive, only that small form factor SSD. I wouldn't be surprised to see built in CD/DVD players to be left out on more models than currently as well - USB attached ones are fine for occasional users and lead to a smaller/lighter laptop the rest of the time.
Higher end laptops would be available with a 2.5" SATA bay for old fashioned hard drives for those who need the extra storage - in addition to the SSD they'd boot from.