Do you really want a gift from your friend - i.e., would you be upset if the gift giving stopped? If so, why?
I get the feeling that your friend is trying to say, although indirectly and probably directly would be better but she doesn't want to upset you, that she would like the gift giving to cease and you are not taking the hint. This does not mean that she wants to distance herself, as you suspect. There could very well be valid reasons why she needs to stop buying gifts for friends, reasons you don't know and she doesn't wish to divulge, or it might simply be that she no longer wants to do it, after all, it's now reduced to you giving each other the same thing, (a bottle of booze), which is somewhat pointless, I think.
I have friends I think the world of, but we do not give birthday gifts regularly (only for significant birthdays), nor Christmas gifts. I value my friends for who they are, not for gifts they might give me. I think your friend wants to stop the gift buying and receiving, but this does not necessarily mean she wants the friendship to cease - you go back a long time, therefore ask her outright if that is what she would prefer and accept what she says. Why do you think she is manipulating you? If you think this, then what kind of friendship do you have - maybe it's time to ease off? I don't know - only you do and only you can decide what is important.