You said it was a weak criticism. But you agree, you're comparing something which you think is "cheap" to something which you think is "pricey". So, not a weak criticism in my mind. It's as simple as that. If I compare two of anything, and one I consider cheap and the other I consider pricey, that's an important factor for me, not a weak factor.
It's a weak criticism because it only focuses on one of the few elements the D&D Starter Set where has an edge on the Pathfinder Beginner Box: price.
The D&D box could have had a similar layout and ease of accessibility. It could have cross referenced between the rulebook and the character sheets. The D&D Starter Set could have been more than the Basic Rules edited down for size and paired with an adventure.
All of that could have been done and kept the same price point.
I could go on and on about the price. I could point out that the average 14yo should have an allowance in the $7-14 range, so they can purchase a $20 product in two weeks. Something that you don't save up to purchase, something that is not anticipated, is less valued. Or how $20 is low for a gift product. Meaning it will either be paired with another product of equal so-so value making the set fight for attention, or ignored for a more substantial gift.
But this is all irrelevant because the price is irrelevant in regards to the actual quality of the product. Value, yes. Desirability, yes. But quality... if the desire is there to really make the product amazing, to make a product stand out as much as the Pathfinder Beginner Box then there was nothing stopping WotC.
Just look at what the PF Beginner Box looks like:



(from the free expansion material on Paizo's website.)
It's bright and vibrant and clean and so very accessible. They spent so much time tweaking the format of options than they decided to change the presentation of magic items in the main product line.
The Starter Set is solid but it's got some pretty giant walls of text. And most of the rules is right out of Basic unmodified.
I'm not going to say they phoned it in. Some work was put into the adventure (by freelancer Rich Baker). And making the rules easy (by the design team). But neither did they go above and beyond. They didn't try and make the best Starter Set ever, to reinvent and improve the starter set experience. They just set out to make a better Starter Set than the last Starter Set. Which would have been fine had Paizo not done something very different a few years earlier.