In my opinion, there are many reasons that restrict the performance of POW coin, such as bandwidth, storage space, memory size, CPU performance and so on. But these are not the most critical factors, the block time is the key factor.
Nowadays, most POW coins are packaged by a very small number of mining pools and large miners. However, we do not think that this will weaken the decentralization and security of POW coins. So can we also think that even if running a full node requires higher-performance hardware, making most PCs unable to run a full node will not weaken decentralization and security too much.
If the above assumptions are correct, then bandwidth, storage space, memory and CPU performance are no longer bottlenecks, and we can significantly increase the block size to improve TPS. For example, if we limit the annual storage space growth of the blockchain to less than 100T, then it is possible to get 10,000 TPS.
In this case, the block time will become a bottleneck. If the block time can be shortened to 1 second, the transfer process will be very smooth. Imagine that the TPS of a POW coin is 10,000, and the block confirmation time is only 1 second, how exciting that is!
So, is there a way we can get the block times so short?
This is an idea we have conceptualised before, but now we don't think so, we are looking for other ways to enable instant trading and have found a preliminary solution, which we are verifying for its feasibility and security.