Some extreme speculation, our ability to investigate exo atmospheres has a long way to go. I'm a little out of date, but no particular mission has launched in the last 5 years to improve the situation, the extrapolation from very few data points was alarming.
Mine was on an exoplanet atmosphere telescope design. When I was working alongside the dedicated atmospheres guys they showed whole spectra plotted against two or three data points!
JWST launches next year? And The ELT should help as well in 10 years or so.
Some extreme speculation, our ability to investigate exo atmospheres has a long way to go. I'm a little out of date, but no particular mission has launched in the last 5 years to improve the situation, the extrapolation from very few data points was alarming.