I don't think it can work. Tipping systems require someone to think about whether they want to tip.
The alternative is what I call "microsubscription": a middleman takes a single fixed subscription, then distributes on behalf of users. Examples include Amazon Underground, Apple Music, Spotify, Netflix, Google Contributor and so on.
Where these fall down is that they're walled or semi-walled gardens. They don't really work on the open web, users have to be funnelled through some central pipeline for reliable tracking of usage.
Which is understandable: open web schemes up until now have had the problem of fraud. Manageable but potentially fatally expensive and offputting.
I'm interested in this problem space for two reasons. First, advertising sucks. It distorts the vision that the early internet held out. We got linkbait and exploitatively addictive web design instead.
Second, I solved the problem of reliably tracking visits to websites on the open web (patent granted in Australia, pending in the USA). As a side effect, the same protocol can be used in apps, games, API calls -- anything that has a network request-response system with some kind of command channel (especially headers). Plus it can seamlessly integrate with paywalls.
Of the microsubscription providers already in service, the one I worry about most is Blendle, because it presents no upfront mental barrier to consumption. On the other hand, it's another walled garden. We'll see.
Tips in the service industry are functionally a means of bolstering income for people who are, by and large, distinctly low-paid workers; developers, even on the low end of the scale, tend not be. I think it's also fair to say that most (most - I realise it's not all) active contributors to open-source projects have day-jobs that provide adequate-or-better income. So what would motivate a common-or-garden developer to court for tips in the first place? And how would a "tip-sized" tip even be noticeable to someone on a developer's salary?
[edit to add: perhaps the issue is the metaphor? A "tip" is roughly what I described above - but it's not actually any different from a "gift", a "donation", or myriad other terms (except, yes, in legal terms of course).]
Reddit Gold isn't really the same; the recipient doesn't really get anything other than warm fuzzies out of it. It's more a way to support Reddit itself financially while dispensing a few of the said fuzzies on the side.
I've had minor contact with a BTC-based tipping system on Reddit, and to be honest it both annoyed me and creeped me out. I forget the name of it, but there was a period where it kept spamming me with "FooUser has tipped you $UTTERLY_DERISORY_AMOUNT, go to $SUSPICIOUS_THIRD_PARTY_SITE and connect up your identities on umpty-zillion different sites to claim it" notifications. I'm not sure who was supposed to benefit in this scenario, but I'm pretty sure it wasn't me.