Capital gains taxes are purely based on profit; you can carry over $3k in losses each year, and that's a "common" tactic, to sell losing positions at EoY to reap the $3k benefit (which can carry over if >$3k).
Why don't we tax capital gains higher, perhaps average it over 5-10 years even, and continue to allow carryover of losses, etc... ? Surely there's middle-ground here that [most] everyone could support....