If you except that the system will fall over, then that's all I'm interesting in.
'Encouraging wealth' is a two way street - if people want to come to this country and enjoy all the benefits of free healthcare, schooling, employment rights, freedom of speech, etc, then they should expect to contribute to it fully. If through tax avoidance any of the services they enjoy will risk being compromised, then that system shouldn't be accepted.
As to the PAYE opt out, you need to satisfy these criteria
to qualify. Something that a lot of people on PAYE (nurses, policemen and other public sector workers, for example) will find impossible to do.