I haven't noticed many IRS Beta systems for sale. Of those I have seen, many have been bastardized with substitute parts and even alternate cabinets, so it's hard to tell exactly what the seller is offering.
I have an IRS Beta system that replaced an RS1-B system. Yes, the woofers need to be refoamed every decade or so, and it's smart to keep some spare parts on hand. But I plan to keep my Betas for at least as long as I remain in my current house. I've heard many fine speaker systems since I bought the Betas, but none have ever made me want to change speakers. The Betas continue to reveal the improvements of my component upgrades over the years and they are, truly, an integrated, full-range speaker system. I can't imagine what they'd cost to manufacture today, although the price of the Genesis systems that are comparable offer some hint.