I see what your saying about tanking but I don't think you should take such a hard line approach to dealing with it. You mentioned that tanking undermines the competitive nature of the game, which is true, but tanking can also be a strategy for long term continued success at the top level.
I started the game around Season 23. Each season I competed to the best of my abilities with winning the league championship being my main goal. I managed my finances well, built up my arena and made what I thought were good purchases. This strategy worked reasonably well until I got to the Div 1. Attempting a championship run, I managed to put together a financially sustainable roster with 4 NT players, and only 1 player older than 32, but I was only able to make the semis. I just didn't have the financial depth to compete with older teams run by strong and experienced managers. Some of those teams, who didn't even seem to be competing for the championship, probably had many millions in the bank while at the same time fielding better rosters than mine.
At that point I could have stayed on the same path, remaining reasonably competitive, but probably not winning anything for the foreseeable future. I choose to tank however, because I thought it a better long term decision that would allow me to come back stronger and be a future perennial title contender in Div 1.
Also, taking away tanking as a strategy at this point seems a little unfair seeing as so many older teams have already benefited from it, some doing it even before there was a salary floor.