Apple’s (AAPL) iPad has one big advantage going for it that the iPhone can’t match: it doesn’t rely on wireless carriers to be distributors. Barron’s points us to a new note from Bernstein Research analyst Toni Sacconaghi outlining the reasons why it’s “highly unlikely” that Apple’s share of the tablet market will ever fall to the level of its smartphone market share. The most important factor, writes Sacconaghi, is that “the iPad has stronger global distribution through Apple stores, carrier partners and network of resellers, including third-party retail outlets (e.g., Best Buy, Wal-Mart, carrier stores) and third-party websites (e.g.,” In contrast, the iPhone is distributed by just 240 carriers worldwide, which Sacconaghi notes is “significantly lower than Samsung (005930) and Nokia (NOK), which have essentially global distribution, and Blackberry (BBRY), which is distributed by >2x the number of carriers.”