A few years ago, virtually all of professional sports were sponsored by crypto companies. Since almost all of them have folded, usually under massive fraud, and have been replaced by gambling firms. So I guess nothing has changed.
There is absolutely no evidence that Bitcoin is being "held afloat by manipulation". It is also a very liquid market: billions of dollars in daily volume.
> BTC has close to zero barrier to entry
That's wrong. Mining power is a big one. Some other barriers: developer mind share, network effect, branding, perceived fairness in initial distribution, software ecosystem, etc. If it was easy to "replace in a second", it wouldn't still be the top cryptocurrency.
Like I said, you might want to reconsider your sources of information.