I think if you are doing to make a fast buck, then it is very difficult. If your aim is to buy, renovate and then live it, then it is still worth it.
We have almost completed a very small scale doer-upper. 70s semi, put in new windows, bathroom, cloakroom, GCH, oak flooring, carpets, replastered the whole house and painted. Oh, and new internal doors. We still have kitchen to do, and the garden.
The house is now worth about what we paid + what we invested, so no profit.
We could have done it cheaper, if we had been doing it to sell, and would have made a small profit, but not sure it would have been worth the hassle and the work involved. If we'd done the work ourselves, it would have been a lot cheaper.