Yes, Intel at least has modified their newer processors: link. But new variants are being discovered all the time, and are being patched in operating systems: link.

The problem with the software mitigations is that they can reduce performance, which matters a lot for big datacentres. 'Speculative execution' - the 'spec' in 'spectre' - was designed to run programs faster, and the fixes, especially the early ones, tended to negate that.