When someone talks about long term investment into crypto coin, this sounds really funny. What long term are you talking about? They all get out of dated in less then three years,
Bitshares isn't supposed to be static. The altcoins which die like that have developers who simply stop innovating. If the developers continue to improve and evolve the blockchain then the blockchain will remain relevant. Also the community around the blockchain brings value to it in the form of exclusive opportunities.
When another blockchain comes along which offers better technology and more innovation than Bitshares then I'll have to agree with you but right now no other blockchain does what Bitshares is specialized to do. Any other blockchain which tries would have to copy Bitshares and then build a new community and ecosystem. This gives Bitshares first mover advantage in the decentralized exchange/financial platform just as Bitcoin has first mover advantage in cryptocurrency and just as Ethereum has first mover advantage as world computer.
It doesn't mean there will not be competition because there probably will be a second place, so you might have SAFE Network and Tauchain compete with Ethereum, you might have NXT compete with Bitshares, you might have Litecoin compete with Bitcoin, but the point is each blockchain is so unique in what they offer, and has different communities and businesses around them, they all will likely make quite a bit of money if you look at the potential amount of money out there.
Hundreds of billions of dollars could be out there, and Bitcoin is currently at around a 5 billion dollar market cap. This would mean there is room for Bitshares to reach a billion dollar market cap, provided that the services and utility brings in enough people that it's worth it. Can other chains offer similar opportunities? Yes but they might not have the exact same opportunities at the same time, they might have different companies around them, and if you think about it like the video game industry then they might have different exclusives.
because better blockchains come out. It is more like a donation to developers than an investment. Sometimes, early adopters make profit only because much larger number of later adopters suffer loss.
But they don't come out overnight, and then no one would know about them which means they'd go through the same community building marketing process Bitshares had to go through, or Bitcoin. They might be better at marketing but still, as long as Bitshares has talented people supporting it, it doesn't really matter if some other blockchain is developed.
A group of banks could spend a few billion dollars building a blockchain which is far superior to anything out there and it wouldn't change the fact that a lot of people would choose to be loyal to Bitshares because of the unique business relationships they've developed and unique UIAs on Bitshares which the bank blockchain doesn't have.
As for BTS, it has a special purpose as collateral and fee token. As a user, you need only enough of them to satisfy these needs. For spinning up bitshares ecosystem, it does not matter which asset do you hold or trade. Centralized exchanges don't issue any special tokens at all, and yet some of them are quite successful.
Centralized exchanges do have exclusives though. The only reason people used MasterXchange or Holytransactions is to access the UIAs of Omni. People use Counterwallet to buy and trade in certain tokens or to deal with LTB. People use Bitstamp to deal exclusively with Bitcoin. And you have centralized exchanges which deal with a lot, but maybe the issuer of the UIA exclusively launches the crowdsale on one particular exchange and that forces everyone to use that.
So I would say the exclusive opportunities are what drives growth. It's not a matter of copying what is already offered elsewhere but to offer stuff which isn't offered anywhere else. Bitshares 2.0 lost a lot when they got rid of interest on Bitassets but didn't replace it with interest from a bond market or anything else, but Bitshares also gained a lot of new features with 2.0 which people haven't yet figured out how to use.