Indeed. 4 strikes and you are out seems fine to me (as a UK driver). You can also opt to take a speed awareness course in leu of the points, I believe

4 strikes today with current speed enforcement is fine; 4 strikes in a hypothetical where 100% of infractions are caught, I aver will catch (almost) everyone who actually drives within a month.

Where I live almost every main road now has average speed cameras, leaving only the small residential streets without, and they are generally short enough that few people are speeding anyway. In general I approve, especially in residential areas, although the surrounding area has gone through a process of downgrading speed limits for no obvious reason, such that it seems their only intent is to annoy drivers so that they want to stop driving. Almost all the country roads in the county I live adjacent to were downgraded from national speed limit to 50mph about 10 years ago. It didn't seem to be anything to do with safety, just seemingly out of spite. I heard rumours that they were also trialing drones to spot offenders (and presumably with sufficiently good cameras to read the plate from up high). Recently, many residential places have dropped from 30mph to 20mph pretty uniformly, again seeming nothing to do with safety as it's entire suburbs (but not all suburbs in the city), even on long straight roads with excellent visibility that would have been safe with limits above the original 30. Doing 20 on these seems completely unnecessary and it's hard to see it as anything other than a revenue generation tactic.

If notice of the infractions is a envelope delivered days later and sitting on on end table for a week, typical drivers are going to rack up 4 strikes before seeing the first one!

Perfect enforcement has to come with immediate feedback

I remember a case from decades ago when someone went from clean license to a ban within 3 miles

Agreed.

You may be amused/horrified to know that the UK police managed to send me a speeding ticket letter for a car I'd sold 6 months before the offence.

I only owned the car for a week, to sell on behalf of my partner who had moved abroad.

I think what he is trying to say though is that people will start to drive slower, especially if they need to drive to function/get to their job.