There were discussions about this. Some were in favour (most noticebly @thecryptodrive), but the majority was against it; including myself.

I can only speak for myself, but the reasoning was quite logical. The SPS is very similar to the reward-pool. It's just more fine-tuned on achieving results, instead of just having a playground for people to co-operate. So taking the cut from the reward-pool makes sense.

In contrast, witnesses are the backbone of Steem and its ecosystem; which includes Steem Engine & co. Taking from that source would possibly mean pulling the rug from underneath.

Witnesses in the TOP 20 are making roughly 9280 STEEM per month; backup-witnesses are making far less (roughly 1/4 or lower). 9280 STEEM at 0.4 USD is ~3712$. (Brutto; tax has to be subtracted) Infrastructure is roughly 400$-1000$ (or more); depending on factors like full-nodes, hivemind-nodes, etc. But this only includes hardware costs, not the costs associated with the individual(s) behind the witness. Besides the obvious requirements as in securing & monitoring nodes and reviewing code, there are many unspoken requirements from witnesses; taking part in discussions, answering questions, helping new/old members, etc etc.

Now imagine BTC would drop to 3000$ and STEEM were to stay at its current level; this would result in a 12 cent STEEM. 9280 STEEM would suddenly only be worth ~1110$ (Brutto). At that point, maintaining a witness would still be possible, but a far bigger risk-factor, as the costs of running Steem nodes are essentially only rising (MIRA is helping, but TOP 20-30 witnesses do have to run high memory nodes in order to keep replay-duration low).

Especially, as infrastructure costs are really just the fundament. And you want to have experienced witnesses that feel their time is valued, which includes adequate payment.

"Even a symbolic 1 or 2 % would have gone a long way to showing that we are all in this together."

I'm obviously not arguing with you that a 1% cut wouldn't really matter in the great scheme of things, but then why even bother with doing that, when the logical thing to do is to reduce the reward-pool in favour for the SPS pool (as I explained above).

Just because people would have a better feeling, as in we're all in this together? That's just sugar on top. Because what if I told you, that we're already in this together?

I'm a witness and developer for sure, but I'm also a content creator. Over my 2 years here on Steem, I've produced 283 posts. That's probably not as much as really dedicated content creators, but its still something. So yeah, the reward-pool cut also effects me directly.