Linux's And Open Source Software's Excellent History
Linux (and the whole open source movement in general) got its reputation for solid software and rapid fixes when this software was used mostly by a relatively small group of extremely knowledgeable people. They knew what they were doing, and generally ran their software on stable, proven hardware platforms; or, when brand-new hardware was used, it was used in fairly generic ways. (For example, video card drivers for Linux tended not to support exotic feature sets; Linux video usually operated at fairly conventional resolutions and settings.)

This is a benign development environment. Any software can succeed if it's placed only in the hands of a small group of knowledgeable experts who can avoid many problems in the first place, and participate in rapid repair of any unavoidable problems that do occur.

And "rapid repair" was a very real thing: The open source arena tended to attract some of the best and brightest of the world's computing community; people who wanted to do good, and whose contributions were almost always positive, focused on the continual improvement of their software.

But things changed. The open source community has fragmented into myriad competing segments, each with its own different, and increasingly quasi-proprietary, distributions of software. Huge numbers of new users of all skill levels have entered what once had been an experts-only enclave. (Even Wal-Mart now sells cheap PCs with Linux and open source applications preinstalled.) It's much harder to produce software for an audience of all skill levels running who-knows-what hardware, than for an audience only of experts running a limited subset of known-good hardware.

And, not trivially, as the Linux/open source segment has grown, it's finally attracted the attention of crackers (malicious hackers). You see, crackers like to aim at the fat part of the bell curve because that's where the most potential victims are. That's one of the primary reasons why more people try to hack Microsoft software than any other: If a malicious hacker wants fame or notoriety, Microsoft software is the obvious target because more people use Microsoft software than any other.

And to me, this is a key thing: When the Linux/open source community was tiny, few hackers bothered to look for exploitable issues there. It simply wasn't an attractive target. In other words, it wasn't so much that Linux and similar software were truly free from exploitable holes, but simply that no one was trying to find them.

But again, that all changed as Linux and open source software entered the mainstream. Now that this software is a fully viable alternative to conventional commercial software, an inevitable consequence is that more problems will come to light. As novice users, funky hardware mixes, and active cracking all come into play, the bug counts are going up. In fact, way up.