The obvious answer is that software is complex and you need Subject Matter Experts (SME’s) to have the depth of experience and the time/role to evaluate all the solutions to provide an informed analysis of the focus, pros and cons of each solution provider. That is a 100% accurate answer. It’s just not the complete answer.
The other reason, simply put, is that people lie. Yes that’s harsh and perhaps a more politically correct statement is that they are just sales people trying to win a competitive review and so they exaggerate, or bend the truth, or position a future feature in a demo as what the solution can do. OK. It doesn’t really matter. What matters is getting to the real facts, as perceived by a supposedly unbiased third party, after having done their analysis of the competitors to create an informed POV.
Therefore, software analysts are unfortunately a necessity. But given human nature, it’s a good thing they exist.
What’s the learning? Look for the TPM provider that is transparent about what their solution can do now vs. the demo you are seeing that sometimes show sections that are little more than activated screenshots. There is nothing wrong with demoing a feature or screen shot that is coming as long as they are clear about it being a future release and when it is coming.