There's a lot of confusion about various Bitcoin Forks, so it’s better to clear up things before any upcoming forks. The only thing to remember is that 21mln Bitcoins exist and that’s only how much it’s ever going to be. There will always be other currency types created by forks on Bitcoin network, but the only valid usable currency is Bitcoin. Bitcoin cash and Bitcoin gold are mere altcoins and cannot be spent on Bitcoin network. People claiming that there are 42mln and 63mln Bitcoins in existence because of Bitcoin Cash and Bitcoin Gold forks are spreading the incompetent news.
Nothing’s wrong with a fork, in fact, Dash executes a fork with every upgrade, and it never caused any chain split. Soft Forks like SegWit Upgrade are considered compatible because upgraded nodes can use new features with old ones still working. Contrarily, a hard fork means upgrade is necessary. Any node that isn’t upgraded won’t work. These forks are irreversible. Any fault with the system can only be fixed with another hard fork. Worst case scenario is a chain split.
Bitcoin cash is an alternate version of Bitcoin. It’s equivalent to the amount of Bitcoin, but there is no direct competition between two because all Bitcoin miners either sold their cash or ignored it and kept busy with Bitcoins.
Bitcoin Gold is another upcoming fork expected on October 25, 2017. Bitcoin Gold coins will be equivalent to Bitcoins so the keepers may ignore it or sell it to stash more Bitcoins. Following the same features from Bitcoin Cash, Bitcoin Gold will be an altcoin and have ‘replay protection.' Keeping in mind the mining trend, there is no chance that it can ever replace Bitcoins. Bitcoin Gold is based on the idea of reducing the use of powerful specialized ASIC computers to mine Bitcoins. These systems are extremely expensive resulting in controlling major power by some certain mining pools. Bitcoin Gold will introduce a new algorithm, keeping ASIC from working and promoting the use of GPU’s for mining. This modification is expected to decrease the centralization in the system, but like any other altcoin, it won’t affect the worth of Bitcoin.