@Scott Trench Before getting into it I will mention that I've been a holder of various currencies since 2015, but do not consider myself an expert. I will do my best to explain as I see things, but welcome others with more knowledge to expand and/or point out inaccuracies.
"Bitcoin is similar to hundreds of other cryptocurrencies. Each crypto has it's nuances, it's slight differences. But, at the end of the day, there seems to me to be no particular reason to me that Bitcoin will be the one universally adopted in the end. Perhaps it has odds over, say, KodakCoin. But, why Bitcoin vs. Litecoin? Vs. Ethereum? Vs. XRP"
I think this highlights why more research should be done before making strong opinions one way or the other. As you put it, Bitcoin's value is in its ability to replace other currencies (such as gold or fiat) as a store of value. With that being the case, why would people choose Bitcoin over the others?
Gold is the best comparison, as BTC is often called digital gold. It may not be tangible in the sense that you can hold physical BTC, but the code that surround BTC is irrefutable. I think both of these currencies are complimentary. One is physical, the other digital. As long as you hold your private keys, you will always be in control of your BTC. Just like if you lock you gold in a safe, you will always be in control of your gold. Give it to a 3rd party to store, and that is where BTC and Gold both become vulnerable.
Fiat government currency has shown that it is not a good store of value. The system is centralized to a max and is subject to inflation. BTC will never be inflated. It has a fixed supply that cannot be changed. Fiat currency is constantly being printed, causing it to lose value over time.
Ethereum is a different concept from Bitcoin. The goal of Ether and the Ethereum blockchain isn't really to be a store of value. It is attempting to be a platform for development of Digital Autonomous Corporations (DAOs) as well as as Smart Contracts. This is a different use case entirely than Bitcoin, so I do not really see the two as competitors.
Similarly, XRP was not created to be a store of value. It is currently being used by banks and financial institutions to help with cross border payments and to manage liquidity costs. If I remember correctly, the creators have mentioned that crypto investors should not be seculating with XRP, as the price of the token is intended to stay low. In addition, Ripple appears to fairly centralized compared to other cryptocurrencies.
LTC on the other hand has a lot of similarities with BTC, making it the most obvious competitor. The main reason Charlie Lee created LTC was to improve the scalability of BTC. There are some differences, such as processing speed, but the functionality is largely the same.
So why would someone choose BTC over LTC?
There is an important point that many BTC maximalists will pount to. There is no creator/owner that can be easily pointed to. BTC is a protocal created by an anonymous entity and is now entirely run by the people who make up the ecosystem. LTC, and all other currencies, have a central founder. Even if the coins themselves are entirely decentralized, they still have founders/leaders who can heavily influence the community.
I highly encourage you to listen to actual experts, as again, this explanation was just my best attempt. The two podcasts I'd recommend were done by The Investor's Podcast. This podcast is normally focused on stocks, but they did two back to back on Bitcoin.
The two I recommend are #259 with Dr Saifedean Ammous and #260 with Plan B. The main takeaway I received by listening to these two episodes was the concept of stock to flow, and why this is important when deciding upon a store of value.