A fork most certainly could have happened because of the BU and SPV miners.
As I said, not in any real way, it couldn't.
Those miners make up nearly half of the entire hash rate of the network. If the SPV miners and BU miners began building on the invalid block, then there would be two branches that are just about the same length.
And the moment that the valid chain was 1 block longer than the invalid chain, all miners would abandon the invalid chain. It might even happen sooner if people looked at what was happening and realized they were wasting time and resources. Either way, it wouldn't have any real effect on the valid chain.
Riiiiiiiight. So you're saying that because only a minority of the hashrate chose the Unlimited fork, the design of BU doesn't massively lower the bar for those wishing to design and promote their own forks?
"If Bitcoin can't handle it, it was a failure to begin with"
Yes, but you're not talking about Bitcoin, you're talking about a Bitcoin fork. Bitcoin wasn't designed to let users provoke a fork with the GUI, that's how your Bitcoin fork BU was designed.
A fool and his money are soon parted. That's the way bitcoin (And the world) works.
And if you proceed with your present course of action, you will be parted from yours. There is no value in a system that can be so easily denuded of it's Metcalffe network effect when it splinters into several forks per week.
So, I have a futures contract for you: I will sell you 0.2 ULC: 1 BTC, after any BU chainfork. I will buy in bulk. Generous offer, ends at the end of February.