I'd been living under the illusion that Oyster was a clever and smoothly-delivered service for TfL to be proud of. I even have dim memories of reading that they were offering consultancies to other operators around the world in "how to do it".
But how sad the contrast with reality. I too fell foul of trying to attach a railcard with an over-3-years validity to an Oyster. After over a month of trying to get Oyster to the problem seriously, I did yesterday speak to someone who gave the illusion of caring. She checked and said that the limit was exactly 3 years - and promised to try and get someone to extend the maximum-thinkable-duration of a railcard to 3 years and a week once I had explained the problem (which she had never heard of before).
Even when/if the duration issue gets sorted out, the business of attaching a railcard to an Oyster is miserable, and it hits out-of-town Oyster users disproportionately. The London resident has a reasonable chance to choose a quiet station at a quiet time to find a staff member to attempt the attachment. The out-of-town user arriving by train with a new railcard needs to get it attached at a busy station, and have no chance to "try later" unless they are happy to overpay for their travel in the interim. And at the Travel Stop that I tried, the staff member hadn't a clue that there was even such a thing as attaching a railcard to an Oyster.
Most depressing was that my first attempt at attaching the railcard at a station (before realising the expiry date problem) failed because the card "wasn't registered". I called TFL and asked how I had managed to top up online otherwise: they insisted that it was indeed registered. Wondering whether they had quietly fixed some error when I called, I tried another tube station. Again the same problem: the staff member seemed to be required to enter my postcode. Luckily, I hit a savvy chap who entered a series of zeroes, which seemed to satisfy the system. But I have no idea of whether that fixed the problem, or just over-rode it on that occasion, which would leave me a problem if my next attempt at attaching the railcard met a staff member who didn't know the workaround.
I queried this with the Oyster supervisor on the phone yesterday. Oh, that was a well-known and long-standing problem: even if you register a card online (is there any other way?), the system needs a manual operation at a ticket machine to make it work. That sounds ridiculous. Is this really true, or can anyone here give me a more convincing explanation of why my card kept coming up as "not registered"?