20-Year Prospect
The greeting card industry, like most industries that trade primarily in paper products, are taking a ruthless bashing in our internet age. The twenty-first century is calling, and the greeting card industry is having a really hard time answering the phone.
Don't get us wrong. Greeting cards are still a big thing; an $8 billion thing to be precise (source). But the numbers aren't great, even if you're a huge company like American Greetings and especially if you're a freelance writer for a boutique greeting card company.
If you're still passionate about greeting cards, you have two life rafts: (1) the millennial generation's obsession with customizing their gifts ("I bought you this handmade card that, though I didn't make it myself, nonetheless demonstrates my unique and wise frustration with our modern capitalist society"), and (2) the digital e-card.
If you have computer programming skills, and know your way around computer animation, you may be able to market yourself towards large corporations and organizations looking for holiday cards en masse.
But otherwise…with maybe one or two exceptions, the best and the brightest of today's greeting card writers will be extinct.