Boxed text has many points of potential failure that lead to that "checking out"
@Morrus and other folks mentioned. For example, boxed text can...
- Assume mode of travel / directionality of PC travel that may be false (e.g. "to your left is a golden archway surrounding impenetrable darkness, to your right is a barred wooden door"...wait we used passwall to come in through the floor!)
- Boxed text may focus attention on something players don't care about (e.g. description of an armoire which is a concealed door...when really that is "stage 2" info that should be offered only once a player expresses interest in the armoire).
- It may overstay its welcome (e.g. insisting each room receive same level of description when that's not necessary or just being a wall of text)
- It may leave critical information til the end ("....and there are also 3 ogres") as a sort of add-on that's not integrated into room description, or worse comes after meandering text and players' attention is flagging so they miss important detail or miss mention of monsters.
I think boxed text can work wonders – but that requires effectively prioritizing information delivered, needs of the GM as intermediary between adventure & players, an understanding of clues/foreshadowing, and walking that line between "just the facts" & artistic emotionally evocative description without becoming boring or unclear.
That takes effort: understanding the encounter & iteration on the writing.
Because of thin profit margins on most published adventures, this is why in the OSR you often see "bullet point" descriptions of rooms. It's harder to mess up bullet points intended for the GM to put into their own words. The one drawback is that this offloads some burden onto the GM's shoulders to figure out how to communicate certain things (info priority & clues/foreshadowing in particular), without giving the GM guidance/teaching on how to do that.