It would be hard to argue that Apple's decision to leave out the floppy drive didn't cause the situation we had 5 years later.
It wouldn't be hard to argue that at all! (#)
As I said, CD writers were already getting cheaper by the late 90s, and Apple can hardly claim credit for hastening their adoption since they didn't even include one.
Yes, the 1.44MB floppy format's capacity was already outdated and starting to look badly out of sync with the sort of file sizes and uses common by the late 90s (cf. the rapidly-growing capacity of hard drives, and the amount of data already-widespread CD-ROMs could hold). The pressure for a replacement was already there in the PC market, the only problem was that no realistic alternative at a practical price had received universal adoption by then. Apple's abolition of the floppy didn't provide a solution at all, it only forced their users to buy external floppy drives.
At best, as the other guy suggested, Apple provide a marginal level of forward pressure to something that would have happened anyway.
If anything, what Apple *do* deserve some credit for is encouraging the adoption of USB, whose time had- or should have- arrived by then. And even that was available in PCs at the time- the one I bought 3 or 4 months before the iMac came out included USB, the problem was that it wasn't that well-supported, and there seemed to be no hurry to do so. So maybe they helped that- and it could be argued, indirectly helped the adoption of USB pen drives several years later- but even that was by forcing the issue (i.e. abolishing legacy ports), and I suspect that USB would have taken off eventually anyway. At least in that case they included a realistic alternative, unlike with the abolition of the floppy.
(#) I think your nickname gives away your slightly partisan nature