I've always argued the same way, but think about the number for a second-- what I'm about to work through is nothing like rigorous, but mainly illustrating a concept:
Apple buys Adobe, and half of Adobe's customers leave immediately. Immediate write-off of something like $400m in operating income.
Apple's operating income is about $4.4b, about half of which is from Macs. If killing the Windows versions sell 20% more Macs, Apple would have broken even.
I'm too lazy to find all the exact numbers, but this isn't too fantastical to imagine...
No, I meant soar. Lets say Apple buys Adobe and (and being the key word) cuts support of all those creative apps for Windows. It will force millions of graphic designers and web developers to buy Macs. Not to mention all those multi-media agencies that fully run Windows (not all creative shops use Macs). That will bring in billions of dollars in sales instantly. Companies will be forced to follow the software that so many of their professionals are trained in. There is no equivalent creative suite in the industry. Despite what people may say about Adobe apps, they are the standard for creative professional. So now think about it. Not only will companies buy Macs, they will also move to OSX server. It is no secret that Apple uses software to drive their hardware sales. And that is exactly what this would do. This would create a serious blow to Windows market-share. And that is how my AAPL will go through the roof.
Since these are essentially the same arguments, I'd respond to both that this outcome is wishful thinking, and represents a huge risk to Apple. Maybe it does work out in the end as has been suggested, but even if it does, this could easily take years to occur, and in the meantime Apple is lumbered with merger woes, which will be a drag on the company and the stock. Just look at the Oracle takeover of PeopleSoft as an example.
A rosy takeover scenario also assumes that Apple and Adobe are actually good merger candidates in the first place, and discounts the issues which always crop up when two large companies merge their operations. Products, fiances, management, culture -- all the impediments I mentioned before, and then some. To me, it would smack of the desperation that accompanied Microsoft's efforts to take over Yahoo. And since Apple is in no way desperate, I don't see the potential advantages outweighing the inherent risks.