It’s an intriguing area of study, whatever else it is, and sometimes theoreticians do anticipate stuff that doesn’t become apparent in the lab for years.
I don’t know about faster than light travel (the G forces would be to kill), but faster than light signaling would be a good start. And earlier this year someone allegedly found that this was happening with a beam of neutrinos. Not all that much faster than light, just a trifle. But the fabled tachyon, a particle which cannot travel any slower than light, might have been seen in the lab.
Perhaps, but for every theoretician who brings forth a new understanding of fundamental physics that leads to a practical and useful advancement, there are hundreds more who do nothing with their lives but poke around with arcane and esoteric formulas, while sucking a living off the taxpayers.
Some, like Stephen Hawking, even become cultural icons, while giving back little of exchangeable value to the world. Pardon if I don't hold most of these people in high esteem.