Usually not, at least not in industrialised countries with their high wage level as treasure hunting is very time consuming. From a purely financial viewpoint an ordinary office job is much more suitable to earn money. The vast majority of finds has no or very little financial value. If in doubt readers might want to spend a few days searching with a metal detector. Or they might want to check the archaeologist's official excavation reports. Though these excavations take place at high potential sites the vast majority of finds consist of potsherds and some small corroded iron items. Bronze items are rare and silver coins are considered lucky finds. Gold finds do virtually not occur. Strictly speaking the above is true for Germany but similar conditions can be found throughout Europe. Even the UK finds sound less extraordinary when seen in the context of a very large number of searchers – most of whom never find any financial treasure.
What is valuable today was valuable in the past. At all times people took great care not to lose valuable items. Often enough people were so poor they did not have anything to lose. Besides, the population density today is much greater than in every past period. 200 years ago just 1/10 of today's population lived in Central Europe. In Roman times it was even just ca. 1/1000, in the bronze age maybe 1/10.000. Few and often poor people just did not lose much.
Those who search with metal detectors do it mainly for the trill of finding. They do not do it for the money. This claim was invented by archaeologists to bring private searchers in disrepute. Later it was repeated unverified by journalists in need of spectacular stories. An ordinary job, even at a fast food restaurant, is a much better and more reliable source of income than searching. Searchers do not search to get cheap access to antiquities, just as a hunter does not hunt for cheap meat. Taking time and petrol into consideration buying antiquities at ebay is much cheaper than searching for them.
For the searcher, the main attraction is the sense of adventure and discovery that became so rare in the modern world, at least in the searcher's opinions who are often quite romantic. Hundred years ago members of the British upper class, tired of reading The Times and hunting foxes, went to Egypt to hunt for antiquities. Today, people all over the world enjoy experiencing the local past by finding historical relics near their homes. Financial treasures, however, are hardly found.