Instead of outright banning ICE cars, why not mandate all new fuel stations must have at least 2 charging stations and provide incentive money to do so?
This is not a bad idea however with charging times being what they are going to a "gas" station to fill up your EV like you would with an ICE car is not really feasible. Would you really want to go and spend an hour at a gas station just to fill up? I know I wouldn't, hell I don't have an hour to waste in the first place.
You also end up with the issue that was posted in Tesla thread, where there were like 20 superchargers and a huge line of cars waiting for them to become free.
The reality is that at this point if you can't charge where you park an EV is likely not for you.
But a week is a long time in politics, and 15 years is an age in terms of technology. If you think about the cost of the first iPhone at launch in 2007, and compare it with my current phone which is massively more capable and cost me £180 there is ample time for the tech to improve and for the economies of scale to kick in.
TL;DR Cars have different challenges to phones and it takes a long time to develop new technologies. I also have fundamental issue with government mandating some technology based on some agenda that isn't necessarily going to benefit their citizens.
You are comparing apples (no pun intended) and oranges. When it comes to computational power one of the biggest things is a number of transistors you can cram into your silicone. We been getting better at making them smaller and smaller and cramming more and more of them into the same space. The other part of that equation is ability to run computations in parallel, for example one of the reasons people use GPUs to mine bitcoin is because they are way better at parallel processing. Also don't forget that a lot of improvements aren't actually due to hardware but rather software, it's easy (in a sense that it doesn't require physical changes to the device) to write efficient code that will take full advantage of available power.
When it comes to EVs there are challenges that involve laws of thermodynamics, for example electric motors are already around 90-95% efficient, there isn't much room for improvement as most of the loses come from things you can't do a whole lot about, like resistance of the wiring and friction from shafts and such.
That leaves with battery technology, it takes time to go from a small scale prototype to full scale production, if a breakthrough were to happen tomorrow you can easily expect roughly a decade from introduction to full scale, it took Sony roughly 10 years to create the first commercially available Li-po cell after the technology was invented. Keep in mind that aside from the normal issues of getting something ready for full scale production (like building or retooling factories) you also have to design for safety, these are cars after all and they will get into crashes just think of the Rimac that Hammond crashed and how they couldn't put it out because of thermal runaway.
As for economies of scale, the one thing most people seem to overlook is that we already have economies of scale for EVs, they all use basically off the shelf components. Electric motors are all basically the same and we have been making them in a million different applications for over a century (your car has an electric starter motor, it's design isn't massively different from what drives a train or a Tesla). And the batteries that these cars use are in your smartphone, laptop, tablet, headphones (if you use wireless), smart watch, vape, etc...
There is also the fact that it takes time to develop and certify new cars and I simply don't think that 15 years is a realistic timeline given all the challenges.
Forgetting all of that though, the problem to me specifically is that this is a government mandate that is going to disproportionately affect middle and lower classes and without any real positive impact.*
*Yes yes global warming bad, CO2 is evil blah, blah, blah, go after the supertankers, container ships and those giant floating hotels that people take on cruises, they produce way more emissions and can spread the cost way more evenly.
