Is possible to upgrade the blockchain technology solving issues like the transactions taking too much time to finish without compromise the currency we have now or without creating a new version devaluing the currently one?
In my opinion upgrading the system of the blockchain is not a option of solving the problem of transactions ( mainly in confirmation ) .
Because all this depends upon the online nodes in the whole world . In I remembered that last time online node was about 350 out of 8333 node( previous day ) .
You can understand easily why problems of unconfirmation happening .Numbers of transactions are more than the numbers of the nodes online .
I think Here. one and only one solution is to putting some news nodes systems only and increasing the reward to support the node system ( because I know that about one of them is rewarded once a week which can be disappointing for those who always making desire that he will get weekly money/bitcoin as reward)
you are completely wrong!
whether there are 10 nodes or 10 billion nodes, it doesn't matter for number of unconfirmed transactions. nodes are ensuring the security of the network and like a bakcbone of bitcoin network. they also help relaying the transactions.
in any case block size is the problem causing the issue here! a block can only take in a limited number of transactions while there are more transactions waiting to be in a block (more than the capacity)