I respect you for being honest, it's a good debate to have and to understand both sides. In really slow traffic it is indeed better to just hold your lane and moving unnecessarily can result in tailbacks behind.. For me, part of the reason cars make so many lane changes is the capacity reduction of the road caused by a lot of drivers today not moving over when they could and trucks overtaking each other at 0.2mph difference. Combined with high traffic levels its a recipe for congestion. A 3 lane motorways these days are really reduced 2 lane motorways and the logic above is contributing to the problem that you claim to be avoiding. You see it all the time folks pull onto the motorway with an empty inside lane and move straight to the middle. If you're saying its less safe to change lanes, why force me to because you don't want to move over?
As for risk, the best way to reduce the risk is probably have the hard shoulder on one side of you which will be largely be empty and just slow down to the speed of the traffic. The traffic is often compressed and slowed around a middle lane driver but many probably think that's normal traffic?
The general rule I use is if it's going to take me more than 10 seconds to get past the next vehicle I pull in and let those going quicker than me move past. and yes sometimes I get slowed down slightly waiting for a time to pass a slower vehicle, but its not just about me, its about everyone else using the road too.