Estimates shows that state-level factorisation will be readily possible by 2030, and academic-size factorisation by five to ten years after that (this is just using classical computers).
Mooore's law has the number of transistors doubling every 2 years (not for sure faster transistors, just transistors). So for 10 years we get 2^5=32. That seems well short of a billion and it is generally accepted that current technology is going to run into fundamental physical limits fairly soon.
Ignoring physical limits, if Moore's law holds it works out to 60 years for state level attacks on 2048 bit RSA.
I mean, Moore's law is hanging but that doesn't mean that they can just, you know, expand their computer footprint? To be precise, NSA (or is it NRO?) is preparing for a warehouse-size supercomputer and it is conceivable that other countries are bucking up with this.
Plus, after the "let's rely on Moore's law" tactic, chip design has another boost of investment, and it's paying off. IPCs, despite the clocks hovering around 5GHZ, is increasing and specialised chips and immersion and/or sub-zero cooling can boost this further. It's rather exciting after the relative stagnation last decade.