Current quibbling over what Jeb Bush meant when he said it’s time to phase out and replace Medicare ­— as opposed to “attacking the seniors,” as one woman at a recent event bellowed out — will soon seem quaint against the realities of our future. Never mind projections that the program will only be able to finance 86 percent of its obligations by 2030. Or that by 2050, the number declines to 80 percent, according to a recently released Social Security and Medicare Boards of Trustees report.