There's lots of angles on this as you can clearly see.... and as a user of filters and blending unbiasedly I see the benefits of both. To say that filters are a waste of money is a wide sweeping and dare I say misinformed statement. The likes of Joe Cornish obviously have a vested interest (to a degree) to extol the wisdom of using filters (so would I, if I were being paid to do so). However this doesn't mean they are a waste of money.
I have no idea why people get so hung up on all this .......... its simple...
You have to produce a photograph, you have an armoury available to you, you use what works best for the situation you are in! How is this difficult to comprehend. If you happen to have a full range of weapons in your armoury all the better, it multiplies your chances of success.
It all boils down to a few things and the skill set of the individual photographer ....
Do you know how and when to use filters, and more importantly can you use them effectively? In todays "Instant" world people pick up an SLR shoot landscapes and expect results, but its not quite like that is it? It takes a lot of practise to perfect the technique, as with anything.
How good are your LR / PS skills? If you are very experienced at post production, then you can easily whistle through processing 100 landscapes that's great. Equally you must also ask, do I prefer to sit in front of my monitor for hours in PP or would I rather be at the business end of Photography "Taking Photographs".
IMHO with a fairly experienced photographer its a question of balance (Moody Blues

). You use all the tools available to you. If you don't have filters, you have an alternative of blending, or with filters in the right circumstances and the knowledge you can save some PP time, or combine both.
If your relatively new to photography, give yourself time to develop (excuse the pun). Use what you have and learn to use it effectively. Prove things for yourself don't believe that "You Tube" is the oracle.
There is no doubt you don't NEED filters because today you can manipulate everything in PP. However they are a very useful addition to your armoury

.
That's all a bit high brow for me

, but its just as I see it, at the end of the day you just use what works for you and more importantly what your budget allows! At the end of the day its the person that take the photograph not the equipment, as they say.