The problem with your log-linear model isn't that it's not updated regularly. I know you do that.

The problem is the *extreme* laggyness of the model, and how you intend to use it. By the time your regression picks up the fact that we are in a huge bear market*, it is already much too late.

The log-linear trend can maybe, if you insist, be used to get an idea of the order of magnitude of the expected price, assuming nothing about the growth function up to now has fundamentally changed. And even then you should remind people that it is no guarantee either, just a reasonably motivated model.