DIYers simply fall for the fluffy dog, Dulux spend a fortune on marketing and clearly aim their products at the uninformed amateur. Prices have continually risen whilst quality has dropped. When you use the products every day it doesn't take long to notice the differences, and so when forced to seek alternative products you quickly realise how bad Dulux are in comparison. They have failed to invest in R&D to provide usable water based products, whilst companies like Bedec (which is pretty much a couple of blokes in a shed) are producing top quality long lasting and very usable paints at a very reasonable price.
I feel Dulux have bitten off the hand that fed them for so long, we can no longer trust the brand to deliver the longevity and finish expected from a pro, and the products are not conducive to delivering a job in a good time frame, i.e. poor coverage - extra coats, and slow drying times - extending the completion time, the message they are sending is they don't care about the trade business because they are not supplying products that do the job, have many times have you heard the name zinsser when discussing problems on this forum? and how many times do you hear Dulux's name come into the same threads?
Just the other day in Brewers, there's me and two other painters in there laughing at the new trade branding, its appalling, at least a client used to be able to see the clear trade branding on a tin, but now it looks like anything you'd pick up off the shelf in B&Q, massive fail (again)
Sikkens, little green, F&B (modern emulsion), zinsser, Bedec and Johnstones all provide superior products. Premium brands such as LG are more expensive but the dulux diamond and LG intellimatt for example aren't that far apart in price but miles ahead in quality.
Read through any painters forum and you will see moan after moan after moan about Dulux and its well deserved.