I, for one, take little delight in dramatically rising LBC values.
I do not plan to sell in the future, if anything I am more likely to be buying. In addition, rising values drive up the cost of insurance and (to some degree) the cost of parts. Higher prices also force some people out of the market or out of the hobby who I would like to see more of -- especially younger owners and active drivers.
Ultimately the value can reach a point where many may be uncomfortable driving the car in traffic -- not that I like driving in traffic but that is usually how I get to the 'good stuff'.
I understand that for those who see the cars as an investment they will sell, rising prices are great and it also helps us justify the money spent on these things, just saying it isn't automatically good for all.