I think some people here have a misunderstanding on what equivalent means. What it definitely not refers to is perceived difficulty.
I hold a german diploma in a natural science, this degree is equivalent to a MSc in the British or US System as it encompasses roughly the same requirements, workload, curriculum and examination standards. For that reason its not equivalent to a Phd nor to a BSc, honors or not even though depending on which exact courses you compare, the difficulty may vary greatly. (a BSc at Uni A can be way harder to achieve than a MSc at Uni B)
The biggest difference between a university degree and other forms of training or apprenticeships is that a university degrees primary purpose is not to prepare you for a job but to qualify youfor academic research in your chosen field by scientific standards. That doesn't make it better or worse, it's simply a completely different approach requiring a very different skill set and things to be taught.
Therefore an ATPL can never be equivalent to a degree, aerospace engineering or something else, independent of how much experience you have or how difficult you perceive it to be. The goal is totally different (flying safe and economical in a commercial environment compared to academic research) and it therefore requires a completely different approach to training. To give an example, it would be completely unreasonable and unnecessary to teach ATPL students the Navier-Stokes equation and the level of math required to understand it as it would be to teach an aerospace engineer meteorology. Or for the ATPL student to conduct a wind tunnel experiment and for the engineer to be able to fly proficiently in instrument conditions. For the respectively other however these are essential parts of their training.
So people stop trying to gain respect for your / our profession by trying to make it into something it definitely isn't just because you perceive it as something difficult. I agree wholeheartedly with PDR on this.