SO WHAT! Microsoft laughs to the bank every single day because your CFO doesn't talk to the CIO or CTO about why this solution must get rebuilt every few years.
Why does this sway your CXO's mind so easily?
What causes people to have a herd mentality and be so fiscally irresponsible?
Yes, Windows is almost everywhere.
But when a new version comes out it doesn't FORCE you to upgrade your hardware. Naturally more RAM is always nice but you don't HAVE to go buy a 64-bit laptop to run it.
If I knew I had to go out and purchase new equipment and redesign my network every 3-4 years JUST FOR EMAIL because the vendor required it, why would that be a good business decision on my part? And if you argue it does more than just email, I would counter with the premise that you now MUST UPDATE YOUR WHOLE INFRASTRUCTURE!
I want a consistent solution from a company that wants to limit my downtime, reduce my expenses, and provide upgrades which I can maintain in a reasonable fashion with minimal disruption to me, my staff or my end users. I have that with Lotus Notes & Domino and ALWAYS have had it from day one.
The next time you hear your executive talking about going to Exchange, ask them about how they feel about the "solution" from Microsoft and the expense related to it that just keep billing you and billing you and billing you.