Back to the OP, are you saying that:
1) laptop hardware has poor reliability
2) PC hardware is unreliable, regardless of whether it's packages as a laptop, desktop, or whatever.
3) Windows and all the other software on a PC is unreliable?
The only interpretation I would personally agree with is (3). PC hardware is very reliable. i've been using the stuff since before the IBM PC even existed, and am struggling to recall a single hardware failure other than a failed disk drive. I can't think of a single one.
On the other hand, I can recall several times that various devices got sent flying out windows because the software didn't work, and without working software, the hardware is just a paper weight. The problem is Windows and the plethora of marginal quality add-on software that makes up a typical PC.
What many have found, me included, is that if you get a windows system working, then lock it down and don't change it, it will pretty much run forever. But god help you if you change anything, "upgrade" anything, install new software, or add new hardware. I always allocate a full day of battle when faced with any required update or addition, expecting o take that long to get everything working again.
Fortunately, most PCs used for navigation are locked down as described. I suspect that laptops get a bad rap because they get used for everything and anything, so are constantly getting updated and revised. Thats not a formula for stable, reliable operation.
Getting back to hardware, disk dives will all fail. It's just a matter of when. And I'm frankly amazed that they hold up as well as they do getting bounced around in a boat. Solid State Drives are a perfect fit for a boat nav computer. They are not infallible, but the risk of dMage is much less, they are much faster, and use less power. I don't think there are any down sides.