Credit card signup bonuses have bounced around a lot over the years. Normal when I started was 15,000 miles. Bonuses surged tremendously around 4 and 5 years ago, it wasn’t uncommon to see 100,000 mile bonuses at least for less popular cards or in the form of targeted offers.
For the most part things have settled down, where 50,000 miles is a good offer and sometimes offers fall to 30,000 miles. Miles are more expensive to issuers than they were in the depths of the Great Recession, and they’ve gotten more sophisticated figuring out what it takes to earn back revenue from portfolios of customers to cover acquisition costs.