"Advanced training"...horse hockey. You're trying to add ratings for bragging rights and nothing more. This isn't furthering education or seeking advanced learning. You're trying to put ink on your ticket to show you've got something others don't, and you've posted here, starting numerous threads in multiple forums, to state just that.

You've also complained that you make too much money to change jobs, advertising what you're making (over half a milion a year, was it?) with your "golden handcuffs."

You can afford to buy a light twin and stick floats on it, or go buy an aircam, or whatever it is you want to do. You can hammer out the commercial without needing the fifty hours, but it's the ATP you want. Not for a job. You're too "handcuffed," for that, but just to brag. You've been hemming and hawing about this for what, two years or more now? Three? Hopefully that level of indecision doesn't show up on the line.

Most who get their ATP in category and class (eg, airplane, multi-engine sea) do so after getting it at the commercial level, and working, gaining the experience, and then going for the ATP (in the rare cases it's needed). They're doing it to use it, as opposed to doing it for show.

Why should the FAA (or anyone else) care if you're being discouraged from bragging rights? You're not being discouraged from a career, or a job, or even an altruistic "advanced training" or higher level of enlightenment or education.

If getting that rating is really that important to you, then either:
Get it at the commercial level and fly off the hours, or
Add it to your CFI and go teach it and fly off the hours, or
Go buy an airplane or rent an airplane or fly off the hours, or
Tilt at windmills and crusade to have a paltry fifty hours reduced in the regulation, or
Make a decision and stop whining about it.

How many more threads to ask this same thing again and again, from this angle or that angle?

If you wanna get the MES ATP, then it's gonna cost you. Or you can work for someone who will pay for it, for you (there are a few...go work for Bridger doing Part 135 for several seasons in a light twin or single, and eventually you may get selected to train in their twin otter...they bought a twin otter on floats just to get people hours and ratings, to put them in the CL415. Done. Of course, you don't want to give up those golden handcuffs for bragging rights, do you? Perhaps it comes down to paying for it, vs. earning it, in order to brag.

Fifty hours isn't just about doing the bare minimum qualification that most do, ten hours or so, to add on a "fun" float rating. For a multi engine sea, where two engines can be a benefit, or a problem when dealing with docking, crosswinds, rivers, etc, fifty hours isn't much. While ATP is glorified instrument rating, you're asking for privileges to act at the ATP level and the ability to hold yourself out as capable of operating at that level. Fifty hours isn't much of anything.

Unless, of course, it's just for bragging rights.