Young people these days don't send New Year's (greeting) cards as much as people in middle age.
Young people these days don't send fewer New Year's (greeting) cards than people in middle age.
▶︎ Young people these days don't send New Year's (greeting) cards as much as people in middle age.
近頃の若い人は中年の人ほど年賀状を送らない。
▶︎ Young people these days don't send fewer New Year's (greeting) cards than people in middle age.
近頃の若い人は中年の人より少ない年賀状を送る。（年賀状を送る数が少ない）
年賀状は日本特有の文化ですが、欧米でもクリスマスあたりのホリデーシーズンの挨拶もSNSで済ませたり、ネットの影響は大きいですね。
日本 
