Whilst the above statement is true, the absolute number of SSB contacts is increasing. To get a true reflection of what is happening, you would also need to take a view on a lot of other factors.
- Where is the increase happening.
- Where is the increase in activators happening and do you need to exclude some associations (is 2m SSB practical for USA and Australian associations)
- Current sunspot cycle effects with 10m wide open most days and with an antenna possibly easier(vertical vs horizontal) than for 2m SSB.
- How mature is the association
Only by doing something like that could you say its in decline and even then with caveats. Its similar to the FT8 argument that FT8 is killing ham radio since 90% (an oft quoted figure) of qsos are now FT8. But are there less of other modes? I would suggest not by much. So infact , FT8 could be seen to be having a positive impact as there are more qsos overall , just the ratio of them has changed.