You are absolutely correct that there are many thousands of books available free. My own library is now well over 5,000. Yes, I will never be able to read them all. I also have a pretty large music collection, though nowhere in the 5,000 range.
You are also correct that the iPad and other reading devices are limited. Though I don't know of any documentation that the device(s) were not designed to contain vast ebook libraries-- it is a reasonable assumption, based on the use of thousands (now millions of users). Is this a limitation? Absolutely. Is it a limitation that most users understand? Maybe. Is it a limitation that most users can overlook? Absolutely. If you can't, I can understand that too. Then the iPad and other reading devices currently on the market may not be for you.
I imagine that it won't be long until we have tablets and ereaders (maybe only with a software upgrade) that can index tens of thousands of titles. Obviously computers can handle large numbers of files like that. But then there will probably be someone who says the device is limited because it won't handle their 5 million books.
All of our electronic tools are limited in some way or another-- either because of current technology, because of the vision of the designers, and sometimes because of simple expedience. It was probably the latter in the case of the iPad. The designers of the iPad could have created a device to easily handle tens of thousands of media files. It might have cost slightly more, and may have taken more time to get to market. But they, apparently correctly judging by sales, decided that most people wouldn't use their iPads in that way. They may have been swayed by the fact that users of Sony Readers and Kindles took those same limitations in stride. Do I know that's what happened? Of course not. It's a guess. It seems reasonable though.
Well say +5 thankâ€™s