There are actually many reasons artifacts and ruins are still being located.

Fire: Although many of the cliff dwellings around Mesa Verde were discovered a century or more ago, fires in the recent past have revealed new sites. Nothing as large as a cliff dwelling, but lithics all the way up to a kiva feature. Fires simultaneously revealing and destroying isn't uncommon.

Drought or heatwave: When a road is well-traveled or a foundation built, it changes how the earth is compacted or may remain below the surface far enough that plowing doesn't reach it (or perhaps the land has been used for grazing rather than plowing). When an extreme heat wave or drought happens, the grass dies, yellows, or grows differently over the area, partly because the roots can't reach as deeply for water in that area. In the UK, former Roman sites, Saxon cites, and so on have been discovered or expanded in this way. These crop marks are especially visible from the air, and during a a massive heat wave in Britain a few years ago, archeologists were using the air to search. In a drought, shorelines retreat and items under water become visible...shoreline villages, sunken boats, whether covered through natural means or man-made damming. This even happens with modern lakes...in Texas, during a drought some years ago, we surveyed a man-made lake bottom on a relatively new lake. Prehistoric sites were revealed because the previous covering brush had died under water and the water was gone. There were newer items, washing machines, junk cars, lost jewelry, and fishing line, too. If this happened two centuries from now, those junk items would have been considered artifacts.

Lidar, ground penetrating radar, and satellite imagery: This mostly agrees with your remote comment. Being able to see the surface of the earth in swaths without having to hike it all has revealed massive ruins throughout Central and some of South America that were totally unknown even five years ago. An excavation I was on two years ago used lidar to reveal prehistoric sites on a former ranch turned state park. Roads covered by sand can still be seen with satellite because of the change in density on well-worn paths. Follow those roads, and you find sites...camp sites, unknown villages, docking areas, and so on.

Flood, soil shifting, farming, and erosion: The earth is not static, it shifts through wind, water, slides, occasionally tectonics, animal activity (packrat nests are a wonder, but moles, gophers, fox, any digging or burrowing animal can reveal things). This shifting both covers and reveals artifacts. A river shifting course, silting up, or any number of natural processes can cover or reveal sites. The Heroine steamboat in Oklahoma was revealed when the Red River shifted its course. The boat had been deep in the middle of a cow pasture, but by the time it was rediscovered and excavated, it was once again in the center of the river. Sometimes underwater, sometimes above depending on how high the water was running.

Burial: Graves tend to be deeper and are less easily discovered without some of the above occuring. Many people were buried with grave goods, such as coins, that might eventually surface through soil activity described above.

Climate change and human use: items, burials, former villages are discovered in areas like peat bogs as they are cut for use. Ice melts to reveal things hidden under layers, but these artifacts also decay if organic because of their new exposure. . Norwegian archeologists can run surveys across melting glaciers, in Greenland Inuit and Norse sites are being discovered (and destroyed, as much decays quickly upon resurfacing).

Clearing land, land use change: forests become pastures or pastures become farmlands, land is cleared to build something new, and earth is disturbed in a way it hasn't been before.

Building over: King Richard iii is an easy example here, he was under a car parking lot. Which had once been a garden or land under an estate. Which had once been the monastery in hich he as buried (likely destroyed during the anti-Catholic movements in England, but this is not my particular field). London is an entire city built upon a city built upon a village and so on. Buildings burn, rubble may be cleared or covered, then built on again, and artifacts can be found in yards, gardens, behind walls (think, shoring up an established but crumbling basement with another wall, but then doing repairs later). Saxons built over Roman ruins...freely available building materials, cleared flat land, etc. Then others built over Saxons. Mexico City is built over an Aztec city and lake.

The interest question: Archeology and interest in history and what came before is both new and not new. Folks have always been interested in history, but in general, survival and ease of material acquisition came first. In the 19th century, what became the early foundations of archeology would be looked at as looting today. (Things like collecting and display without context, mummy unwrapping, just willy-nilly digging....the search for Troy...Schliemann dug through layers of cities just trying to get to his goal, destroying without leaving a good record, among other things). Stonehenge, Roman and Greek sites, really any sites would be used to build new villages. Why quarry stone when stone is readily available in this ruined building over here? Holy places might or might not remain sacred to the next folks to live in an area, but most building sites were likely considered sources of free material. (Again, easily seen in older British villages that may have homes built from stone or brick from the local destroyed castle, saxon village, Roman villa, smaller henge stones used for marking the border, etc). It's a luxury to have readily available building material today, rather than having to make it yourself. Coins, pots, points, jewelry, and such were probably discovered and maybe used/collected/spent, but a broken piece of pot or a piece of a rusty weapon would likely have been tossed aside. What use to a farmer is a potsherd? There are many ranchers with a collection of arrowheads found while working cattle. A few landowners with a mound they won't tell archeologists about because they don't want it disturbed, think the archeologists will take everything, they're digging it themselves, they don't care or realize it's significance, or many such reasons. (It isn't illegal to loot your own land where I live.)

I hope I provided enough specific examples, although not necessarily sources since a lot of my info is first hand and not necessarily published. I hope I answered your question, as well.

Edited for a few typos