This is another "false myth" which was considered in the past.
Turnover of "collectible" (meaning trend games people want) used titles at reasonable prices is not directed or significantly effected in sales data by new machines, except during the period of EM to SS transition in the late 1970s.
It is gradual process not a "spike".
Only newer collectors "run" to new titles as the rest hold back and evaluate. General minority. Used title flucuations are more affected on economic changes in short order.
Sometimes you do see "blips" of collectors selling off their "crap", in order to make room or cash out, but the price you can pay is not a "deal to sell" lately. This can be a regional anomaly.
A lot of overpriced machines based on value misconceptions of "bling" all over the market right now, more than ever.
Operators do not dump older titles as much anymore, if they still make good money and functional or are not payed off.
Broker and dealers indicate steady sales of used machines which peak interest from release of new machine titles.
New machine titles are always a boon to the market, however large or small.