If you are a company, you are in the business of doing (hopefully legal) activity X at a profit.

Anything which gets in the way of your making a profit is therefore not in your interests, and you are going to find it unreasonable to be required to do it.

Now as most of us know well, software companies stand to make a lot more money when customers are locked in - in fact theory says that the maximum profit that companies can extract from this desirable situation is the sum of their customers' switching costs. So anything that increases lock-in is a Good Thing™ from the point of view of a company. (Though not, obviously, from the view of the customers.)

Therefore the provisions in the LGPL, which are intended to make it easier to unlock people by creating a free alternative, is a Bad Thing™. Thus they don't want to do it. Which is why the FSF found it worthwhile to release software under a license which attempts to extract that behaviour modification from would-be users.

In short, if it was something that companies would normally find reasonable to do, then the FSF would have no reason to bother getting companies to do it.

Cheers,
Ben