I suppose it depends. 30 grades for OPE are obsolete, in my view, but that doesn't mean they shouldn't be used. I think there are better choices out there, but that's a lot different than me calling for a blanket prohibition on monogrades. If a straight 30 is called for, sure, use it. But, that doesn't mean that a 10w-30 HDEO wouldn't do the job at least as well.
On the other side of the coin, my lawnmower (which likely calls for a straight 30) isn't worth a pile of money. It's going to get orphaned quarts from my garage (everything from GC to HM to M1 to 0w-40). I'm not going out of my way to pick up a monograde for a cheap, throwaway lawnmower.
Now, if I were working for the city or something and were hired to service many lawnmowers, all which called for a 30 grade, I'd simply go to WM and buy a 5 gallon pail of SAE 30. For a situation like that, it might be worth the effort.