I think the above is a good way to frame the question - as opposed to “How have the arguments of the book stood up?” Because, regardless of how well they’ve “stood” (and I’m not implying they haven’t successfully stood as truth claims - I remember largely accepting them myself years ago when I read the book), another important question to keep in mind is “how well do those arguments engage with current culture?” (And yes - on hearing that, the ‘relativism police’ have alarms blaring, as they rouse themselves into full emergency response mode.) My impression is that this approach to apologetics is largely seen as dated now (as in … yeah - this was your father’s Oldsmobile). Which isn’t to say the arguments don’t still have essential truth to be valued - and still have a needed influence, perhaps especially in getting somebody started toward understanding how Christian argumentation has developed. [i.e. - seeing it more now as an instructive history of apologetics rather than as a definitive last word that compelled seasoned skeptics.] It’s a lay approach probably found on more high school and young-adult shelves maybe than in the scholarly halls of theology. And that isn’t the ‘put-down’ that it may have sounded like to some. My recollected impression is that he was aiming more at a wider and younger audience more than for professors or prestigous theological libraries. Look more toward the likes of N.T. Wright if you want that (who I think might have significant overlap in some of the actual substance, but just written at a higher level.)
All that is just my way of saying that I think I would attend more to Josh McDowell as a current person, and his and his son, Sean’s more recent books - how they are engaging with current culture now. Because in many ways, the questions on people’s minds today are different than those asked a generation ago. It’s also a way of reframing the original question: “how true and sound were Josh’s arguments and truth claims” to add in a different question: “How true is Josh himself?” As with so many evangelical leaders these days, the proof is really in the pudding. Their actions and any lately revealed allegiances proclaim the real message of what they are about, and provide all the illumination that is needed regarding how much you should be hanging onto their words. Can you get fresh water from a salt water spring?
Josh would insist, in fine apologetic and philosophical form I’m sure, that it doesn’t matter where all the interests of culture have migrated, or even what kind of saint or reprobate he himself may have been lately; the answers to life’s persistent questions are still going to be the age-old truth that it has always been. And as a Christian, I agree with that - sort of. The last bit of it anyway, though I would say it very much matters where the current culture is, and yes - the messenger cannot be disregarded whenever we ponder a message. I bet Josh would agree with all that.
You might be interested in a now closed thread from some months back where we went through Myron Penner’s book “The End of Apologetics”. In fact I think he has some enegagement with Josh McDowell himself and has interviewed with him. Link to the thread below.