- "Bitcoin prices only increase"
It depends and is a matter of time. In the short term this is not always true, the opposite, but in the long run, it has been true until now. Bitcoin's price has risen since the first bitcoin was released in 2009, but prices have remained unchanged for a long time. Although Bitcoin prices are likely to become much higher when technology is open, if the problem of scalability and management issues is solved and when network effects are introduced. However, Bitcoin is increasingly competing with Bitcoin Cash or Bitcoin Gold, as well as other anonymous solutions such as Monero, Zcash, or scalable solutions such as Dash and Stellar, or even Ethereum and platforms. Similarly - if and when they manage to solve the scalability question first.
you are getting a couple of things wrong here too.
first the price has never been "unchanged" from 2009 till now. it is constantly changing and most of the times the changes are wild. people call bitcoin a "rollercoaster" for that. it is not just a joke.
then the scaling is not something you snap your fingers and is fixed for good for eternity. it is something you improve upon every step of the way and will continue doing so.
and finally these shitcoins you named are just pump and dump shitcoins, none of them are even scalable. ETH network is currently clogged like a toilet, Monero can't handle large number of transactions and had always had a serious problem, ZCash is not as good as Monero and has the similar scaling issues. Dash is centralized bullshi.
Modern blockchains such as Bitcoin Blockchain are designed in a very expensive way to manipulate transactions. Hacking data on Blockchain is much harder / more expensive than hacking data on a server. Therefore, Blockchain technology can be considered more secure than server-server technology. However, the technology also introduces new types of security risks: intelligent contract security, the reliability of external data sources (oracles), network attacks, fall attacks three hard.