Lie Nelson planes are a premium product, Festool tools are a premium tools which have at least one unique feature. That unique feature may not have value to everyone but to those that do value it will pay for it. Over time patents expire or other manufactures incorporate the same features but by that time Festool has moved on and give them something else to chase.
My experience with Festool gear has been limited mostly to the subcontractors who worked for me who used them. Overall, their comparisons of Festool to other brands was mixed. I used a Festool miter saw and was not impressed. However, for a quite a while, Festool had the best dust collection capabilities. Today, there are portable HEPA dust collectors and power tools on the market whose dust connection abilities are the equal of Festool, and in some cases, better. One of my cabinet installers used Festool equipment. He liked the track-saw and work table a lot. He swore by the Festool dust collector and sanders. He did a lot of kitchen renovations, and he thought that keeping the site clean was a big selling feature, and he was right.
The Festool Domino is a tool that a lot of people love. It provides a stronger joint than a biscuit joiner. I get it. When I was in college, I worked in a woodworking shop. For the first six months, about all I did was make mortise and tenon joints. We had jigs made up, some of them fixed, some adjustable. On a Saturday afternoon, I could bang out a lot of mortise joints with a router. When laminating up large blanks, we used loose tenons that we made in the shop too. Using jigs, you have the flexibility to make any size tenon, accurately and quickly.
I've been using doweling jigs for a lot of what I have been building for several years. I have two JessEM jigs, and they do a great job. I have a Powermatic mortising tool for big mortises, but the doweling jig takes care of about 95% of what I need. One of the great things about woodworking is that there are a wide variety of tools and techniques that can be used to get the job done.