The other problem is that fossils rarely form. So the images of dinosaurs we have now? I wouldn’t bet on them being totally accurate. Though we do have a title image of certain dinosaurs, such as Velociraptor or Tyrannosaurus. But Spinosaurus? That thing practically changes every single week. Then you need a compatible mother to carry the foetus or lay the egg, and to produce the oocyte into which you place the DNA. The longer a species has been extinct the harder it will be to find a compatible dam, and also the less likely you are to find intact DNA.