Weren't most of those microtransactions in bitcoin really all spam made by the supporters or the people behind of bitcoin cash?
Maybe. I suspect so, but I don't think there is conclusive proof.
LaurentMT did some interesting analysis that suggested that the spam attacks were a coordinated effort by several mining pools.
The temporal coincidence in this last observation is rather surprising. One may be tempted to interpret it as a collective answer to a sudden attack but we know that fan-in transactions processed during the 8th wave were flowing on the bitcoin network since late 2015 (see reddit comment quoted below). So, that leaves us with the hypothesis of a coordinated operation decided by a group of mining pools. Remains the question: why did these pools suddenly decide to mine transactions which they were previously ignoring?
The desired effect is obvious enough:
In my humble opinion, a more likely hypothesis is that the goal of this operation was first and foremost social and psychological. Fact is that the perception of 5 full blocks in a row is very different from 2 full blocks separated by an empty block and 2 half-full blocks. By consistently stuffing blocks with “junk” transactions for months, one can subtly reinforce the belief that Bitcoin requires an urgent upgrade increasing its capacity.
I reckon we really do have to question if bitcoin really does need a block size increase today.
It's pretty clear we don't need one right now. We've seen that the fee market model is very robust. Another size/weight increase is probably an eventuality, though, as long as the network keeps growing.
