Does DDR5 make sense for most mid-range builds now?

Yes, the price gap has shrunk enough that DDR5 is the better buy for a new mid-range build. You get roughly 5-15% better performance in games and a tangible boost in productivity for about $30 more than DDR4. Plus, DDR4 locks you into a dead-end platform, while DDR5 gives you a path to upgrade the CPU or RAM later.