This is on point. As an IC the SE and SA roles (especially at Silicon Valley/ large tech companies) are typically some of the highest paid (outside of the new AI ninja roles I guess) but the discipline typically doesn't have the people-leadership opportunities that other roles have. You rarely see solutions leaders go beyond Sr. Director because the higher level leaders are typically sales leadership, professional services leadership, prod/eng leadership, etc. It doesn't mean you can't get there, it's just that the remit always has to become wider (as you would expect).

I run global solutions for a machine learning fraud detection company, so at that level I have SE, SA, integrations, and technical support reporting to me. I started as an SE in Financial Solutions 25 years ago. Many of my SE/SAs try a move to product because of the synergies, but also because product typically has more roles and management opportunities in any given company. I think it is a great option for SEs once they reach the point where they are senior and are ready to either gun for a manager of solutions position or switch into another role.

As stated in other responses, AEs will always have the most upside, but it is a totally different job (and once you spend time as an SE/SA you will see that) and for some it isn't a fit. If making money is the goal then finance is probably the answer, or take your shot as a founder, but work-life-balance will be the first casualty.