True enough, but it does negate a future relationship with God based on race and/or national identity except on the basis of Gospel salvation. Paul only envisages the conversion of Jews in terms of them being grafted back into their own olive tree 'if they continue not in their unbelief'.
There is no other tree available for them to which they can be grafted back in. No other gospel. No other saviour. No other community of the redeemed. It couldn't be simpler, and you don't need a degree in theology to get it either.