If something is in research phase it should not be patented yet. And once invented, a 5-year protection still gives the inventor a 5-year advantage. If it cannot leverage it effectively, sorry but too bad.
No method is perfect, but I think that in most cases a 5-year protection is enough to encourage invention.
Many products contain hundreds of distinct "inventions" in the patent sense. One can't necessarily hold off on registering a patent for an individual invention for 5 years while the rest of the product is developed, as you'd risk a competitor inventing the same before you have patent protections.
Patent does not protect a product, but a specific technology. If 1 technology out of 10 in a product is under patent protection the competitor (and the public) cannot copy the product as is, but is welcome to use any expired technologies any way it sees fit.
In general, it is a business decision on whether to patent a technology that it is not ready for the production: the risk of not making a product in 5 years vs the risk of competitor getting there first. It is not perfect, but I would prefer that inventions that the owner wants to own (and suppress competition for) but cannot commercialize in 5 years enter public domain. My 2c.
No method is perfect, but I think that in most cases a 5-year protection is enough to encourage invention.