If a product of yours is currently end of life, or NLA, would you want to pay someone to dig through your old archives, verify the information as correct and have to host it for a product you no longer sell?
For current chips yes i can agree, again it comes down to, if the chip isnt selling in large quantity, nor expected to, why do i want to pay that guy to check it and upload it, or they have some deal with another buyer, so they have them, but they are keeping them quiet unless asked for,
with most of these things, you can find "something" on them if you dig deep enough, i myself had to try and dig up the programming datasheet for a panasonic cpu used in a subaru radio, lets just say i found enough, but i was in corners of the internet that no search engine could get you to,