Blockchains seem to split every time there is a contentious upgrade. The blockchain cryptocurrency that wins out will be the one that is most widely accepted. The best way to think about it is that it is a fair inflation. It's (almost) instantaneous and fairly distributed to all those, who hold the legacy coin. Fears of too much dilution are pure FUD. Dilution is only bad, when it robs savers of their money. If savers have double the coins after the inflationary event (fork), then they were not robbed.
There are other effects, of course, like (possible) splintering of acceptability and therefore utility, but classic inflation is not what is happening.