No, its not your fault that you were a poor student, but it is your fault that you decided to use a digital distribution service, knowing full well that you lacked the means to back up any data you download from them.
As for the variations of DD services, again, it is up to you to either find a way to keep track of what you used in the past, or if you are not comfortable with that, only stick to a handful of services that offer what you are comfortable with (such as Steam and Impulse).
Maybe I'm just misunderstanding your point, but you seem to blaming the services for their distribution methods, when you were the one that lost track of your information. That's like accidentally losing an original game CD or losing the manual with the license key printed on it, then blaming the store you bought it from, as if they were somehow responsible for you not taking proper care of your purchased item. The fact that you used a DD service doesn't excuse you from your responsibilities as a consumer.

Dude, external HDDs are less than $50 (sorry, I don't know what that would be in your currency) and well worth the expense, not just for backups of DD games. I highly recommend you look into one.

That's laughable, especially when there weren't alternative sources to obtain the game yet. I paid a legit full price to support the developer. Yet most "digital distribution" sources offered mirrors to re-download your games, should you lose the installer files. It's the matter of how one source differs from another that irritates me. In fact, for certain games, most sources do offer re-downloads, but the one that I can pay direct to the developer offers a mirror that expires after a while. It's not the consumer's fault that some digital distribution platforms are less than what is expected.
As for the variations of DD services, again, it is up to you to either find a way to keep track of what you used in the past, or if you are not comfortable with that, only stick to a handful of services that offer what you are comfortable with (such as Steam and Impulse).
That's what I'm doing right now. Of course like you said, as an alternative, I can keep track, maybe using notepad. If you're happy with just being able to play the games which you supported the developer for via fixed amounts of donation, by all means go ahead. But don't call it the consumer's fault for those of us who feel wish there was something to make digital distribution more mainstream and unified.
It's ironic. My University lecturer uploads some of her reading materials on to the school's forum for individual students to download. Upon clicking on the Download icon, the file can never be downloaded again, because of copyright issues. In a way, it reminds me of certain DD sites.
In another case, the whole idea of burning the installer into your own CD also reminds me of how I used to store my torrented games...

So I guess I wasn't misunderstanding, because it still sounds like you are saying that it is the DD service's responsibility to make sure you don't lose your data, not yours. If so, then I have to say your expectations are quite flawed. The fact that you are provided the data via a method other than physical media does not excuse you from taking responsibility for keeping that data safe and available, just like with your physical media. Just because some services are nice enough to provide you that extra feature of being able to re-download for free certainly does not mean that all of them will do that and you really should not expect that from them. Even those services that do allow repeated downloads are not guaranteed to do that forever, we've already seen it happen here with TOCA 3.
If you don't like it when those services don't offer redownloading, then don't use those services. If you do use those services, then you need to take responsibility for it and you have basically lost the right to complain about it, since despite your issues with the distribution method and not being able to take the necessary precautions to protect your data, you chose to use it anyway. We are talking about games here, it's not like you needed to get that game, you wanted to. You took the risk of your own choice, that makes it your responsibility. Not to mention, as a consumer, if you don't like the way a company does business, you should tell them that by not giving them your money in the first place.

All that and more, but it still does not mean the state of digital distribution can't improve, or is perfect as is. TOCA3 was a good example provided btw. I have nothing to say against that.

Thanks for bringing up this app...I've got it installed and I'm slowly getting my game library in there. Nice little program. Plus, I can keep all my serial keys in there as well, so I have a back up of those somewhere.

You're welcome :)
Yeah, there's lots of room for customization regarding what kind of info you want to store in there.
Very nice for a free app.