I do not think that’s a fair description of Mahasi Sayadaw. Here are just a few quotes from him that I believe offer a more holistic assessment:
“Some people talk disparagingly of concentration meditation. The Blessed One himself had however recommended cultivation of the concentration meditation too. When jhanic concentration is achieved, that concentration can be used as an ideal basis for meditation. (Commentary on Anattalakkhanasutta: 71)”
"After thus ensuring the purity of his sila, the Bhikkhu should strive for attainment of one, two, three or all four jhanas. If unable to do so he should work for gaining at least the access concentration in the neighbourhood of jhanas. If he cannot work separately for the jhanic concentrations, he must try to achieve the khanika samadhi (which has the same characteristics of suppressing the hindrances as the access concentration) by contemplating on the four primaries. etc. This does not involve establishment of concentration as such but by keeping close awareness of the true nature of nama, rupa concentration automatically arises. But by having the attention dispersed over many objects or having it fixed on objects which are not easily discernable, concentration takes a long time to come about. Confining to limited objects which can be distinctly noted will facilitate and hasten development of concentration.
Therefore we are instructing our yogis to start with noting vayo dhatu … in the region of the abdomen. (Commentary on the Wheel of Dhamma: 92-93)"
“it is relatively easy to attain the second path knowledge and fruition knowledge fairly soon after attaining the first, but it will probably take a long time to attain the third path knowledge and fruition knowledge after the second. The reason for this is that only training in morality need be completely fulfilled in order to attain both the first and second path knowledge and fruition knowledge, but you must also completely fulfill training in concentration (samādhisikkhā) in order to attain the third path knowledge and fruition knowledge. Therefore, someone who has already attained the first path knowledge and fruition knowledge can easily attain the second, but it is not so easy to then attain the third. (Manual of Insight: 300)”