I remember <script language="Python"> and I even saw it implemented. Alas, everybody deploys the cheapest version they can. Only windows really gave us the variety promised by the language attrib of the <script> tag, since MSHTML.DLL was tied into everything in the OS, so you install Python into the WSH and then iexplore.exe could hand that chunk of text over to WSH for interpreting.
My offer: A world where Lisp-machines were stubbornly preserved, so ALGOL and its children didn't dominate computer programming.