So they make it expensive for people to check bags and they are now surprised that people do all they can to avoid yet another charge?
It probably doesn't help that the road warrior has fully matured now. You can see quite a bit of advice going around that any road warrior will be well-advised to try and keep their travel gear to a single carry on, typically a rollerboard. It saves massive time at the airport, particularly as you do not have to go through baggage check-in procedures, and later do not have to endure the wait at the baggage reclaim.
Giving even an extra free checked bag or a heavy bag for free (i.e. 32 kg piece) will not change this behaviour. Even on this forum, many people will go HLO if they can help it (though admittedly, many here are good enough to adhere to the sizing and weight guidelines); let's be brutally honest -
no one here is going to really recommend that the avid business traveller check-in baggage if they can help it. Perhaps it's only luckily that many people on this forum can actually lift their own cabin baggage (and don't expect FAs to do it for them), and also know how to rearrange an overhead locker if required.
The way I see it is the bad decisions made by airline managements have come home to roost, a short term gain for long term pain type thing...
Perhaps this is quite true.
The difficulty is that now any attempt to control the situation is the equivalent of suicide. The first airline who dares to be draconian on the cabin baggage policy will suffer some sort of publicity wrath from disgruntled passengers complaining that said airline has turned into a bunch of naz_s. The social media furore on the inflexibility of said airline will be plastered
ad nauseum, and the other airline will benefit greatly, even if they enact the same enforcing measures. Certainly you can expect extra stress reports from frontline staff at airports, possibly an increase in passenger rage or assaults / verbal tirades against frontline staff.
So I think the airlines have backed themselves into a corner here that they will not be able to get out of cleanly, if at all.