That is mentioned in the Wikipedia article, but given the fact that þ also hasn’t been used for hundreds of years, I think it would make sense to re-adopt both letters to distinguish between the sounds (though accents will probably make things confusing)

Btw, þ is supposed to be used for the “hard” th (Wikipedia article for the corresponding phoneme with audio sample).

The “soft” th has another letter, ð (Wikipedia).

Wikipedia about the usage of ð (and a bit of þ) in old English