Heh... the experience of learning a new language also transforms your future work in the languages that you already know! It's how you grow in this business... and there's no replacing it.

And the “gurus” who are out there producing “PHP itself” ... do they know? You bet they do! That's the beauty of (and the endless allure of...) this business as a career:   you always feel that you are lucky to be getting paid for doing this. And yet, the digital computer is always your master; never truly your slave.

You now recognize the need to add another powerful tool to your personal tool-belt. Does that, therefore, provide an adequate (business|financial|technical|career) justification to scrap what you have already done? Ditto the expertise you have already acquired? N-O-!!

Never forget the “FISI principle”:   F**k It, Ship It!   :-D

At the end of the (business...) day, “what is done is done, and by the way, it's paying the freight.” What you do in the future is an entirely separate decision.