I don't think this is true anymore, since they recently started rolling out discounts on vehicles, which is usually a sign of overstock / slowing demand [0]

[0] https://www.torquenews.com/14335/tesla-sweetens-deal-discoun...

Their global backlog of orders has gone from ~470k to ~74k over the last few months. There is no backlog of orders at all in the US or Canada and the backlog for the rest of the world is dropping quickly.

https://twitter.com/TroyTeslike/status/1609346097733828609?s... (This is the most recent data made public, the Patreon data goes through Dec 31 with the numbers quoted)

Just to add, I used the 'build a tesla' recently for Model Y and was quoted delivery time of about 30 days. Not sure if that's accurate, but doesn't sound too supply constrained compared to discussions with other automakers I've spoken to recently (6-12 months out in some cases). I backed out because I'm really concerned with build quality issues that seem to be worsening, and generally losing confidence daily this company will be around in 5 years.