The commercial value of coriander was, historically, in the seed. So it was selected to go to seed quickly for financial reasons. Now, more and more people want it for its tasty foliage, but they have to be quick about it or the plant bolts, sets seed, and turns bitter.
If you love having cilantro in the garden, buy some seeds, harvest often and plant it frequently, directly into the garden. If you would rather buy seedlings, select the youngest ones available, preferably those without true leaves. If it looks like cilantro, it is probably too old to transplant.
Yes, we will continue to sell cilantro. And we will continue to sell it as a really young plant and encourage our beginner gardeners to purchase some of their own seed and plant it directly. And we will encourage you to try using other herbs in its place, such as young parsley, chervil, and rau ram (Vietnamese coriander); these plants are not the same, and it is their very difference that makes them so enjoyable.