Litecoin was created on 13th October 2011 and it's the longest running ever blockchain, as it has had 100% uptime. (By contrast, bitcoin has had two downtimes in 2010 and 2013. In 2013, versions 0.7 and 0.8 of the Bitcoin software diverged from each other, causing the blockchain to fork unintentionally - mining paused and the network was down for 6 hours 20 minutes as developers scrambled to fix it, and the price crashed 23%).
Given Litecoin's reliability, it's fast confirmation times and low transaction fees, it's surprising the coin isn't doing better.
In my opinion there are two reasons for this.
The first is Charles Lee's sale in 2017.
Litecoin had hit it's all time high of $375.29 on Tuesday 19th Dec 2017. On Wednesday 20th Dec 2017, Charles Lee announced on Reddit that he had sold all his holdings. The coin never recovered. Even in the crypto bull run of 2021, it only got to $345 and failed to get past it's previous all time high.
The second reason is the advent of stablecoins, in particular Tether. Basically, a significant part of the world's population "just want to hold dollars", and Tether is the nearest thing. They don't care that the dollar has significant inflation, which means the purchasing value of Tether is dropping too.
Therefore, for real world commerce, Tether is used to buy things (though Bitpay and other processors report a lot of Litecoin use).
Finally, Wall Street isn't interested in Litecoin.
Yet Litecoin chugs on, never going down, fees never spiking, and handily it's listed on most of the world's exchanges.