One example was the Hawker Hurricane, which was in service before the Spitfire was developed, and which outnumbered the Spitfire by about three to one in 1940.
TL;DR = That's not entirely true, the Hawker Hurricane entered service 10 months before Vickers-Armstrong Spitfire, but the first maiden flight of a Spitfire happened about six months before the first maiden of a Hurricane.
Spitfire began production on/around June 1936, Hurricane production began, also, in 1936. The first maiden of a Hurricane Merlin II was on 12 October 1937 - and those planes then immediately entered service - but the first maiden of a Spitfire came months prior to the Hurricanes, the Spit's "eight minute maiden" was on March 5, 1936, but while displayed in proper flight later that June (27th) 1936, it didn't enter full scale production until the following summer, and service followed that August 1938.
It was that delay in entering full production and the additional man hours to complete each air-frame (Hurricane took less time to & cost less to build - 10,300 man hours vs the 15,200 for the Spitfire - though the Spitifire, even with the same armament, was much more advanced than the Hawker, but on the same hand, the Hawker the more rugged of the two)... and not to mention that Vickers, the parent company, didn't really want anyone other than Vickers to build the Spitifire (initially). That all conspired to reduce the overall number of Spitfires produced in comparison to the Hurricanes, but only during the lead up to the Battle of Britain. Overall, more Spitfires were produced during the total war effort.
Some 14k Hurricanes were produced (includes Sea Hurricanes), but the first production commitment for the Spitfire was for a paltry 310. Even so, Castle Bromwich (a primary Spitfire production facility) was producing 320 aircraft per month at it's height and a total 12,129 Spitfires were produced from that facility alone and when the last production Spitfire rolled off the assembly line in Bromwich, a total of 20,351 Spitfires had been produced (all variants) - outnumbering the final count of the Hurricane by over 6k aircraft.
While it is true that the Hawker outnumbered the Spit ~3:1 or 2:1, depending on where you get your stats, entering the Battle of Britain, the Sptifire suffered significantly lower attrition rates during those months, particularly the Autumn months, than it's counterpart. Even so, the Hawker downed more enemy assets than the Spit and had a significantly lower R&R (re-arm/re-fuel) time than the Spit, under ten minutes with a good crew for the Hurricane, almost 30 minutes for the Spitfire... So YMMV depending on what you flew. It's quite possible the Hurricane suffered higher attrition rates because there were more of them to shoot at and their pilots never really got any down time. A Hurricane pilot would be lucky to get a bathroom break, where a Spitfire pilot could have a break and a cuppa...
At the end of the war, universally, it is the Spitfire upon which victory fell - both in general estimation and in the hearts of the British people... but for those of my fathers & grand-fathers generation, well, they still argue pro/con Hurricane/Spitfire to this day...