Why can you not update Security systems Firm ware chips Etc.?

I love using Honeywell Products there a good solid engineered product the problem though is Honeywell like every other manufacturer of security panels will not allow you to buy firm ware updates chips.

You buy and install vista 20P Version 1.0 your stuck with it and when Honeywell comes out with some new thing like the tuxedo Keypad Z Wave keypad yep you guessed it the panel you put in 3 years ago will not support it and you have a customer who wants the Tuxedo Keypad and would buy it but not if they have to buy a whole new board.
Why can I not buy an update chip?

Well one answer is UL underwriter Labs. changing the firm where requires testing etc etc. But lets face it folks its a whole bunch of horse shit.
I work on all types of Electronic systems and I can firmware update them I do it all the time with, Routers, Mini Storage control automation systems , EAS radio control systems, which give the emergency alert ,CNC Machines etc etc.

So whats really stopping it. I think its because you could take a vista 32FB and all of a sudden make it a Vista 128FB panel etc.
But why not install the 32 and then when customer is ready to expand buy the update chip.
but as usual in the security field manufacturers never listen to the guys working in the field they build what they think we want not what we really want because the big guys in the industry rule we want an upgradable control we want USB interfaces we want to be able to use any 56K modems to program not 1200baud Hayes etc etc.
Some day they may get it Honeywell and every other panel maker would sell so much more equipment if we could update firmware instead of having to change out the whole board and even sometimes all the keypads. This is not what customers want to do update every time some new gadget comes out