I'd actually argue that the "business users" you refer to don't want a solid old-school, built to last 10+ years, ThinkPad. Really, the retro ThinkPad is something that I'd think can only work as a prosumer product.
Large businesses tend to want something that will get them through a 3 year refresh cycle without excessive downtime, for minimum cost.
It'd be interesting to see what the split between L450 and T450/T450s sales is, as well. I know that my client moved to the Latitude E5440 (L440 equivalent) from the E6430 (T430 equivalent), rather than going E6440 (T440p equivalent) or E7440 (T440s equivalent I think). And, they're going to the E5450 (L450 equivalent) with the next gen.
Current: X201 (i5-540M, 8 GiB, 160 GB), 365XD (120 MHz, 72 MiB, 6.4 GB, 4x CD-ROM, 10.4" TFT)
Past: T61p 15.0" QXGA, T60p 15.0" QXGA, X61 Tablet SXGA+, R51e 14.1" XGA, X21