The 1910-S Lincoln cent is one of a select group of Lincoln cents: the San Francisco dates from 1910-1915. These dates have always been seen as better. They may not be the key Lincoln cents, but they are certainly not readily available.
In fact, the 1910-S has oftentimes been seen as the weak link in the group. Its mintage of 6,045,000 was higher than all the others except for the 1913-S. That made the 1910-S and 1913-S seem more available since as all the others had mintages under 5 million.
The higher mintage probably played a role in making the 1910-S slightly more available in circulated grades. However, none of these dates were easy to find in circulation during the great boom in Lincoln cent collecting in the 1950s.
There is a good deal more to the 1910-S than simply being part of a group of better Lincolns. In 1910 the Lincoln cent was new and a sensation to say the least. There was enormous saving of the first Lincoln cent.
Prior to the Lincoln cent, no American had ever appeared on a circulating coin. The first 1909 VDB Lincoln cents were saved in large numbers.
The 1910-S had a low mintage, but it would not have seemed low at the time. Both the 1909-S VDB and 1909-S would have seemed much lower.
Another factor that must be considered is that the collectors at the time were probably very much up in the air about how they were going to collect Lincoln cents. After all, the idea of mintmarks in cents was still new, since it started in just 1908. No Denver cents had been produced by 1910, so a collection by date and mint might not have seemed logical.
It is natural to see some extra saving the first year of a new design, and that was certainly the case with the Lincoln cent. Usually, the next few years see a continuing decline in the number of Mint State examples because the novelty was gone. Dedicated collectors would have done the majority of the saving.
There is no doubt that most of the 1910-S coins went into circulation and stayed there for a long time. Coin collecting was growing, but the growth was not explosive. It would not cause large numbers of the 1910-S, or any other date, to be pulled from circulation.
When the large numbers of collectors did appear and pull the remaining 1910-S cents out of circulation, it was the 1950s and the coins were lower grade. As a result, the 1910-S in G-4 lists at $8.50 today. In fact, it does not get above $20 until you reach XF-40. The 1910-S is fairly available in lower circulated grades.
In MS-60, the 1910-S is currently $65. That is a pretty good deal considering its age and fairly low mintage. It is also well below some of the other San Francisco dates of the period. This raises some doubt as to whether the price reflects the actual numbers available, or a figure based on the mintage totals. In MS-65, the 1910-S is currently $800. Again, it is below the other San Francisco Lincoln cents of the period.
The grading services are not conclusive. In most cases the 1910-S is slightly more available than the other San Francisco dates of the period, but not by so much that you would expect the current price differences.
The 1910-S might just be a little undervalued and due for an increase in most, if not all, grades.