Peter Schiff argues that Bitcoin's scarcity is void because other cryptocurrencies will keep the supply ever expanding. While it is true that other cryptos receive value that could have gone to Bitcoin, let's compare this to how value actually works by looking at the value of domain names:
Initially there were only a few TLDs (top level domains) available such as .com, .net and so forth. This has been expanding throughout the years and really been ramping up in recent years. Does this mean .com names become less valuable because money also goes to these new, more niche TLDs such as .guru and .network? No! On the contrary, .COM names for instance keep increasing in value because the more varied the space becomes the more we put value on the "main one" which has the most conistent, perceived value.
So like TLDs, the altcoin space will expand to fill evermore niches, in the process it will harden Bitcoin's stance as the premier coin to own.