The genius of satoshi was in the cryptographic field, and most importantly, having the vision to put all the (already existing) pieces to form a new thing. PoW was already there, distributed networks with nodes were already there, he just made a pack and it worked. The code was rough, apparently it lacked a lot of fine tuning, but that's not important when the concept is genius and it actually works in practice.
This is why someone that is a better coder could come up with another cryptocurrency, but if it's not a game changer at the scale of what Bitcoin was in 2009 (and still is) then it's not going to get anywhere, the network effect is too strong in Bitcoin.
Whoever wants to challenge Bitcoin must come up with with a completely new way to solve the Byzantine General's problem and do it in a much more efficient way, which I doubt it's going to happen for at least 100 years which is what these big problems usually take for someone to come up with new solutions.
bitcoin is falling out of favor with outrageous fees and being congested during peak hours. And appears to have become political. There are lot of other coins catching up to fill that avoid. But I agree, it is still the dominant coin but I am almost sure if not something significant being done, another coin will catch up in the next few years. IMO.
My biggest gripe is mining, no longer mineable by small-time GPU-ers like me, and as far as mining concerned, it is not decentralized anymore.
What the core dev-s are doing against the ASIC mining is not certain. I am working on platform to be able to switch many hosts into any coin and bitcoin (and other asic compatible coins) is/are not even in the consideration for obvious reason.
Sure, Bitcoin has it's problems, but something that scammers typically claim is how their altcoin is going to solve Bitcoin's problems, only to find out that eventually their altcoins succumb when faced with the same problems and deal with these problems even worse, usually by centralizing the network (huge blocks) or by a system that is exploitable (PoS, DAG-Tangle stuff)
There isn't a single coin out there that is objectively superior to Bitcoin and solves it's problems, if this was the case, everyone would dump and sit on that other network, but guess what, that doesn't exist.
The "Core devs" don't have enough power to do something about mining. All they would create is yet another altcoin, because I doubt the rest of the community would follow, unless the idea was complete genius and long lasting.
I can not say for sure, personally I'd rather bitcoin succeed as dominant but the way it is now with super high fees, and other problems, not sure. And it is not jus I am saying many people is concerned about it. I can not say which one will prevail over Bitcoin and/or which technology will prevail, there is no single person that can analyze 1000+ coin's whitepaper make a judgement, so only time will tell. I myself usually interested in gpu mining and managed to go over few dozen coins only, but the way I see now there are several altcoins that are looking better than bitcoin.