You should expect that every company will not keep older unit updated or serviced. And it's in everything.
If you want to have unlimited support for 5 year, and the warranty and the updates, you must pay for it.
Nothing is free in this world. So a 798 that is sold for 1050$ today, will cost what? 1200-1300$ for 5 years service?
It's a trade off each business has to do. Do we offer unlimited support and high price, or we skip on some things and offer a more affordable product.
Not mentioning if the said unit CAN receive the current update with it's aging technology.
Just to put into perspective, at work, we brought a 300k$ Press brake and 500k$ Laser cutter, and guess what. 1 year LIMITED warranty. After that, pray the Gods or use the checkbook.
What people need to understand, is that when Humminbird decide to stop the support for old units, the unit is working fine without important bugs. Sure, you might not have the newest accessories or functions, but you didn't have them when you brought the unit.
People seem to have taken for granted the yearly update process and new features.
If Humminbird stopped supporting a unit still full of bugs and problems, Now, that would be bad for the user and the company.
This is my personal opinion on the subject.