I think it is just as likely to be a case of selective memory. It is a fact of life that humans tend to remember "bad" things much more readily than positive things. We will naturally pay attention to and get emotional about something that fails just outside of warranty. This attention and emotion will serve to make us remember this incident clearly. On the other hand we will pay little attention to, and feel no great emotional reaction to, items that last well past their warranty period. Hence when thinking about this issue these items will be less likely to be remembered.
Having said that, modern appliances do tend to be made as cheaply as possible in order to increase profits. Cheaply made products will tend to fail earlier than well made quality products. Hence, more products are likely to fail "just outside their warranty period".
Is that "planned obselescence"? Doubtful in my opinion. Firstly, "planned obselescence" is illegal and any company caught engaging in the practice opens themselves to fines. Of course that does not mean no company would attempt it just because it illegal. Secondly, to intentionally build a product to fail within a specified period would actually take more research, development and planning than to simply build a product as cheaply as possible. So why would a manufacturer decrease their profit per item for an uncertain and unspecified gain in future sales. Thirdly, consumers tend to dislike items that fail just outside of warranty and therefore are less likely to replace the item with another by the same company. So it is unlikely that any gain would be realised by the practice anyway.