Sure, go ahead and show me your "data structure traversal", in Javascript (JIT'd is fine, since clearly non-JIT is just out of the question), that works in 3-5 cycles.
The whole topic of this conversation is a measurement in which it was claimed that "a billion DOM operations per second" were being done in 2015. That's a concrete number. Show me the actual DOM operation that can be done a billion times per second, in 2015.
The burden of proof here is on you, not me. I'm making the perfectly sensible claim that all you can do in a low-single-digit number of cycles is run a loop. I have, in fact, shown in other languages down at the assembler level that things that claim to be running in .6ns are in fact just empty loops, so I'm as satisfied on that front as I need to be. It's not exactly hard to see that when you look at the assembler. You don't even need to know assembler to know that you aren't doing any real work with just 3 or 4 opcodes.
I don't know how you expect to just Measure Harder and get a billion operations per second done on any DOM structure but I expect you're going to be disappointed. Heck, I won't even make you find a 2015 machine. Show it to me in 2025, that's fine. Raw GHz haven't improved much and pipelining won't be the difference.