You are missing the point. For Crossrail to be competitive in journey time between Reading and, say, Tottenham Court Road the trains would have to have a limited number of stops, or preferably be non-stop, between Reading and Paddington. Otherwise people will not use the Crossrail
trains between Reading and Paddington but will use the fast trains and change at Paddington.
As half the eastbound trains through the Crossrail platforms at Paddington will start from there the chances of getting a seat at Paddington will be pretty high. You won't need to get on a Crossrail train at Reading to get a seat on Crossrail.
Non-stop trains to the Crossrail tunnels are unlikely in the short and medium term since
- the Mains are pretty full at the moment and there is not the capacity to add another four paths per hour in the peaks - the minimum I would suggest for a competitive service
- new Crossrail rolling stock would be needed - the trains being built have a 90mph top speed which is incompatible with 125mph paths on the Mains
- a grade separated junction would be needed to reach the Crossrail tunnels from the Mains
So, it's a nice idea - but won't happen soon. So no need to make remarks about Reading being fortunate enough as it is.