brute forcing a private key being it 128bit or 256bit is impossible today it's stupid to even try, and I've already provided the math for this and we do not disagree on this, my point is, in the next few decades we will eventually reach the point where we will have enough computing power to be able to do so as happened in the past!
No we won't. You seem to vastly underestimate how large 10^70, 2^128, and 2^160 are.
In 40 years Moore's law has provided roughly 1*10^6 improvement in transistor density and a roughly comparable improvement in cost per unit of computing power and power per unit of computing power. It is highly likely that Moore's law will not be sustained for another 40 years, Intel may actually slip below that "benchmark" for the first in this decade. The cost to build smaller and smaller process nodes is increasing exponentially and the time between process nodes (which should be no more than 24 months) is slowly inching upward. Lets not even get into the fact that there are only 8 maybe 9 process nodes before we get down to the transistors using 3 atoms a piece.
Still lets assume that an equivalent amount of improvement occurs over the next 4 decades. That is a ~10^6. Today top supercomputers are PFLOP scale. Lets ignore the fact that Integer performance is often a magnitude worse and that it takes tens of thousands of operations to complete a single keypair (and even more to perform lookups). Lets just naively assume that 1 ECDSA key generation and lookup can be done in 1 FLOP (which doesn't even make sense but trying to be ultra conservative). That would mean today a top super computer could do ~34 PK/s (peta keys per second). To keep the math simple lets just round up to 100 PK/s or 1*10^17 kps.
If we then assume a 1*10^6 factor improvement in relative performance in the next 40 years that would make a top SC something on the order of 1*10^23 kps. Now lets assume you build one for every man woman and child on the planet (estimated to be ~10 B in 2054). That would put world wide key breaking power at 1*10^33 kps. You aren't even within the same ballpark as 10^70.
In reality performance will probably slip below Moore's law, you can't process on key per clock cycle, and even if you could we are looking at an energy requirement greater than what is used by the entire human race for all other purposes.