Hard shellac 78 rpm records would wear out crude inexpensive steel styli after a small number of plays. Todays laser cut diamond styli last a lot long longer because vinyl is a softer material. However the forces at play as a stlyus traces the microgrooves of a vinyl record are sufficient to both cause wear on the stylus and wear at a location corresponding to the contact area in the microgroove wall. This type of groove wall and stylus wear can be heard as a loss of high frequencies and may not be noticeable for dozens if not a few hundred plays of a certain record but developes on the stylus with every side played and so loss of high frequencies on any record is more likely due to a worn stylus than a worn groove.
If a record is so old as to have been played so many times (and with earlier less capable equipement) for groove wear to occur, changing to a stylus with a broader area of contact may recover high frequencies from a section of the groove wall that has not been worn.
In addition to gradual wear over time however excessive stlyus wear and groove damage can occur with mistracking and poor cartridge set-up. Groove wall damage typically occurs over a large section of the groove wall resulting in permanent loss of information encoded in the groove wall. Mistracking typically occurs in the more heavily modulated passages and where the cartridge is furthest from the ideal alignment such as the innermost track. The better the table and tonearm is, the less mistracking occurs - provided the cartridge is correctly set up.
The diamond tip is a big cost factor in the price of a cartridge. Less expensive ones use bonded styli - a smaller cap of diamond glued onto a stub. More expensive cartridges use whole "nude" diamonds that can be machined into the more complex geometries that provide the broader groove contact area. Stronger magnetic materials cost more than weaker ones and you don't want a heavy motor either. Finally there is the cost to manufacture and yield; the greater the hand assembly involved the higher the cost.
Moving Coil(MC) cartridges can generally trace higher frquencies more easily because response time is faster due to lower inertia from having a lower moving mass. There are also other aspects of generator linearity and magnetic flux effects that affect performance. Moving Magnet(MM) designs can have a more reliable bass and don't require so much phonostage gain. The tonearm and table will need to be of a higher quality to achieve the sonic potential of a moving coil cartridge than with moving magnet. Thus factoring the cost of a step up transformer or moving coil phonostage, when upgrading to a moving coil cartridge is a significant step up in investment in vinyl record playback.
kemela can demonstate the sound of various MM and MC cartridges and advise on a balanced vinyl playing HiFi subsystem. We also have a good slection of phonostages.