There is no 'fast moving highway' where the acceleration post 60 of any modern vehicle that has a license plate is a problem. What is a problem is other drivers that make unrealistic assumptions about the capabilities of other vehicles.
I've driven >> 1,000,000 million kilometers in 36 years of driving and to date I've never seen a single instance of the speed of acceleration being a safety issue. Even on short on-ramps - which is really the only spot where acceleration in normal traffic matters - almost every car will do just fine, and in case it doesn't you either stop or use the emergency lane (if that's allowed where you live).
Above 60 you are already in traffic and the differences required to overtake another car are minimal, you can do it faster to be out of the left lane a bit quicker but you're still limited by the speed limit and traffic that comes up from behind will just have to be patient.
What may be the case if this is a situation that you encounter frequently that the problem somehow lies with you and/or your driving style. Most people just want to get from 'A' to 'B' safely and economically, and speed of acceleration considerations don't enter into it at all. Given all the other vehicles that you share the road with, a large number of which are much slower to accelerate than a Prius ever would be the whole idea is to work together to keep everybody safe and get them home in one piece. Not to extract the maximum performance from their vehicles.
Owned one. Had the issue. You’re wrong. Maybe a result of the CVT or low torque at speed not sure but it was unsafe. When you need power to get out of a situation and you floor it and 3 seconds later still nothing…
That is simply a defect, not something structurally wrong with the Prius design.
Did you have it checked out by a competent garage? Prius is a complex machine and needs proper care or it will break. I had a similar hybrid in Canada and it worked like a charm except for when it was < -20 Celsius, then all kinds of weird stuff would happen. Apparently the manufacturer had not really thought about the range of operating conditions that their product would be exposed to. So in the dead of winter when it was super cold acceleration would be underwhelming, but once you know that it is like that you simply don't put yourself in situations where this can be a problem. I've driven 2CV with an anemic 600 CC engine (there also existed an older one with only 375 CC) and it was perfectly safe in traffic, if you worked within the limitations of the car.
In the end it is the driver that matters, not the vehicle and if you put yourself in a position where 'you need power to get out of a situation' you are most likely already at the end of a long string of mistakes. Keep in mind that there isn't a truck on the road that can accelerate as fast as a personal car and yet they are not constantly in danger because of a lack of power.
In practice it seems like if you give people one step forward in acceleration they get two steps picky about what gaps in traffic they need to do their thing (merge, left turn, whatever) resulting in a net decrease in the overall performance of the car + driver system.
