The discussion grew out of the fact that from 1st January 2021 a player like Lewis Montsma would no longer be available to Lincoln City (neither would Joan Luque or Bruno Andrade - the latter would have been unlikely to qualify for QPR's Academy at 13).
The point system itself has nothing to do with Brexit. However, the application of the points system to European players is the direct result of Brexit. The points system is biased towards the large clubs, who are the ones best placed use it to import talent from outside of the UK (especially pay the wages required to attract them). This disadvantages smaller clubs (e.g. Lincoln) who now have a smaller pool of potential players available to them and increases the divide between the top 30 clubs and the rest.
Also, (to my mind at least) 'cheap foreign imports' have not prevented young home grown talent from flourishing. Whether one likes it or not, the Premiership now attracts the some of the best footballers from around the world and most of those are expensive. There is an argument that this has dragged up standards across the rest of football. Certainly, the number of young players who now have the opportunity to learn the game in Academies is greater than it has ever been and I suspect that, overall, their technical ability is greater than their predecessors. There are also more full-time professional teams playing the UK than ever before (down to step 5 and even 6) and more professional players (some of whom hardly seem make any appearances).
However, the Premiership clubs load their Academies with the cream of talent from abroad (using the point system) and release those that don't make the grade. We then see these either disappear from the game, or re-appear further down the pyramid.
The whole system is dysfunctional, except that it is designed to support the Premiership as the premium football league in the World. The changes that have resulted from Brexit (MAY) exacerbate the divide between the Premiership and the rest of UK football, since it restricts the pool of players available the smaller clubs.