In my experience phrases like 'the end of science' or 'the end of discovery' are generally thrown around only with regard to particle and quantum physics. What they actually mean, within this very specific field, is something more like 'at some point we will built a particle accelerator powerful enough to observe everything about particle physics and make all the observations it is possible to make with it.' As a hypothesis there may be some truth to this: the level of power necessary to push through a particle accelerator in terms of making useful observations probably does not extend infinitely, even though we are quite a ways away from reaching that point. This, however, applies only to one specific sub-field of physics. Other sciences make new discoveries and launch new sub-fields all the time. Pretty much no other field is even close to making arguments like this.