Removing the parentheses around year does not work

Question

I have to comply to the style guidelines of some freaking academic journal. As usual, they always let the author do the work, but this one is pretty tedious even from the initial submission. What's left for me is to get rid of the brackets around the year. What I need in particular is this:

As this question has been asked and answered before, I tried to adapt that solution, but it does not work out for me. I include biblatex with my preferred settings in the MWE, but reducing it to 'style=authoryear' as the only option does not help either. Other than the biblatex call, I did exactly as in the linked question. Did biblatex change in the meantime to let this crash?

\documentclass{article}
\usepackage[style=authoryear,sorting=nyt,isbn=false,doi=false,clearlang=false,
backend=biber,natbib=true,hyperref=true,giveninits=false,useprefix=true,
backref=false,maxcitenames=2,uniquelist=false,uniquename=init,
maxbibnames=10]{biblatex}
\renewbibmacro*{issue+date}{%
\setunit{\addcomma\space}% NEW
%  \printtext[parens]{% DELETED
\iffieldundef{issue}
{\usebibmacro{date}}
{\printfield{issue}%
    \setunit*{\addspace}%
    %       \usebibmacro{date}}}% DELETED
    \usebibmacro{date}}% NEW
\newunit}

\usepackage{filecontents}

\begin{filecontents}{\jobname.bib}
@article{Bli74,
    hyphenation = {english},
    author = {Blinder, Alan S.},
    year = {1974},
    title = {The economics of brushing teeth},
    journaltitle = {Journal of Political Economy},
    volume = {82},
    number = {4},
    pages = {887--891},
}
@book{Kop04,
    hyphenation = {ngerman},
    author = {Kopka, Helmut and Daly, Patrick W.},
    year = {2004},
    title = {Guide to \LaTeX},
    edition = {4},
    location = {Boston},
    publisher = {Addison-Wesley},
}
\end{filecontents}

\addbibresource{\jobname.bib}

\nocite{*}

\begin{document}

\printbibliography

\end{document}

Thanks in advance!

EDIT: This is the working MWE, tnanks to Moewe's link in the comments.

\documentclass{article}
 \usepackage[style=authoryear,sorting=nyt,isbn=false,doi=false,clearlang=false,backend=biber,natbib=true,hyperref=true,giveninits=false,useprefix=true,backref=false,maxcitenames=2,uniquelist=false,uniquename=init,maxbibnames=10]{biblatex}

\usepackage{xpatch,filecontents}
\xpatchbibmacro{date+extradate}{%
\printtext[parens]%
}{%
\setunit*{\addcomma\space}%
\printtext%
}{}{} 


\begin{filecontents}{\jobname.bib}
@article{Bli74,
    hyphenation = {english},
    author = {Blinder, Alan S.},
    year = {1974},
    title = {The economics of brushing teeth},
    journaltitle = {Journal of Political Economy},
    volume = {82},
    number = {4},
    pages = {887--891},
}
@book{Kop04,
    hyphenation = {ngerman},
    author = {Kopka, Helmut and Daly, Patrick W.},
    year = {2004},
    title = {Guide to \LaTeX},
    edition = {4},
    location = {Boston},
    publisher = {Addison-Wesley},
}
\end{filecontents}
\addbibresource{\jobname.bib}
\nocite{*}
\begin{document}    
\printbibliography  
\end{document}