And if you’re in the US maybe stockpile a ton of them because companies aren’t allowed to produce incandescents anymore?

I just checked the DoE guidelines on this, and I think fairy lights are actually exempt! Here's the relevant paragraph (bold mine):

A general service incandescent lamp is a standard incandescent or halogen type lamp that is intended for general service applications. It has the following characteristics: (1) medium screw base; (2) lumen range of not less than 310 lumens and not more than 2,600 lumens or, in the case of a modified spectrum lamp, not less than 232 lumens and not more than 1,950 lumens; and (3) capable of being operated at a voltage range at least partially within 110 and 130 volts. This definition does not apply to the following incandescent lamps—(1) An appliance lamp; (2) A black light lamp; (3) A bug lamp; (4) A colored lamp; (5) A G shape lamp with a diameter of 5 inches or more as defined in ANSI C79.1-2002 (incorporated by reference; see § 430.3); (6) An infrared lamp; (7) A left-hand thread lamp; (8) A marine lamp; (9) A marine signal service lamp; (10) A mine service lamp; (11) A plant light lamp; (12) An R20 short lamp; (13) A sign service lamp; (14) A silver bowl lamp; (15) A showcase lamp; and (16) A traffic signal lamp. 87 FR 27461, 27480.

"Lamp" here should refer to each individual bulb. Referring specifically to the Prextex lights you linked: They do not have a medium screw base (=the standard E26 base you see in most house lamps), lumens per bulb is below 310, and each individual bulb is at just 2.5V. 

This explains the lack of any "discontinued" notice or sudden price spikes or panic buying. Also, looks like there are plenty of loopholes for continued incandescent usage. It'll be a pain, and it's a dumb rule, but it's surmountable. This will be yet another area in which knowing the specifics of the dumb rules will advantage some people over others.

I love learning new Smallpox Eradication Lore.