For the most part I agree with this list. Portugal are already making very favourable noises. Greece I'm less sure about.Spain gets the majority but don't forget the massive communities in Cyprus, Greece, Portugal and I'm not just talking visitors I'm talking contribution via business and actually living there.
But I will add that some Western European countries that are very difficult to get a visa for longer stays -- France, Italy especially -- if they haven't made exceptions for US visitors, where the numbers are slightly higher and the spend likewise, they may not make any for the UK.
I suppose the proximity argument might factor in if e.g. a holiday home means much higher spend.