Many people do not realize that these two words originally were contractions.
The word “phone” — spelled P-H-O-N-E — originally was ‘phone — spelled APOSTROPHE-P-H-O-N-E — which is a contraction of the noun telephone, with the apostrophe signifying the omission of the first four letters (T-E-L-E).
The word “blog” — spelled B-L-O-G — originally was ‘blog — spelled APOSTROPHE-B-L-O-G — which is a contraction of the compound noun Weblog, with the apostrophe signifying the omission of the first two letters (W-E).
I believe that writing ‘phone with the initial apostrophe fell out of favor because it is simpler to omit the apostrophe than to include it. Omission of this apostrophe is consistent with my “Devolution toward Simpler” linguistic hypothesis.
I believe that writing ‘blog with the initial apostrophe had almost no chance of success because apostrophes are not legal characters in a uniform resource locator or URL, whereas many authors — including yours truly — like to put the word “blog” in the URLs for their Weblogs.
The result is that both “phone” and “blog” — neither of which have an initial apostrophe — have become accepted words in American English.