This is not the web in which you can choose Safari, Mozilla or Chrom(e/ium) where these 3 programs all operate under the same web / http protocol.
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They can always upgrade to get access to newer features but the web is always the same. There are no two webs.
Could you point me to the global consensus ledger that Safari, Mozilla and Chrome maintain together? No? Then you're making a terribly foolish analogy.