All this is complete nonsense for the illiterate inhabitants, of whom the majority. All those marketing stupid pictures in the press that can create a contrasting image with the lighting in the room.
On a white matte screen, this is a priori impossible. Only in 100% darkness. This is partially solved by a special black screen, but its price is almost the same as for the projector itself, or even more expensive...
On an ordinary matte white screen with a reflectance of 1, you DO NOT need more than 150 lux of illumination on a standard 120" IN TOTAL DARKNESS. Even with effective means of combating reflections hitting the screen - full drapery of the room.
Therefore, all these statements about 2100-4000 lumens are for idiots among the public that does not understand anything. And such devices are idiotic by default, because. do not have cinema modes with low brightness for working in complete darkness on a white matte screen.
To view video content during the day, you need at least 1500-2000 lux for every 1 sq.m of screen area. 106 "is 3 sq.m. At the same time, this brightness should quickly fall automatically along with a change in the illumination of the room, so as not to damage your eyesight.
And at the same time, the projector must be QUIET in this mode, with noise less than 26dB. Which is a priori physically impossible today with the available technologies.
Therefore, projectors will soon disappear as a class of pointless devices, as soon as flexible AMOLED screens roll into a tube, like ordinary projector screens, appear.